Merge pull request #395 from pascalorg/feat/editor-ux-rendering-placement

editor: roof wall openings — doors/windows/items on roof-segment wall faces

apps/editor/components/build-tab.tsx

@@ -1,8 +1,9 @@
 'use client'
 
+import { nodeRegistry } from '@pascal-app/core'
 import { MaterialPaintPanel, triggerSFX, useEditor } from '@pascal-app/editor'
 import Image from 'next/image'
-import { useCallback, useEffect, useRef } from 'react'
+import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
 import {
   Tooltip,
   TooltipContent,
@@ -79,6 +80,28 @@ function activatePaintMode(): void {
   ed.setMode('material-paint')
 }
 
+type RoofFeature = { kind: string; label: string; iconSrc: string }
+
+const ROOF_FEATURE_FALLBACK_ICON = '/icons/roof.png'
+
+/**
+ * Roof accessories surfaced under the Roof tile (a "Features" group). Unlike
+ * the community editor these aren't DB presets — each is a registry kind with
+ * `capabilities.roofAccessory`, enumerated from the registry at render time
+ * (it is populated by the app bootstrap — a module-scope const would race it)
+ * and activated like any structure tool (the kind's tool attaches it to the
+ * roof segment under the cursor). Label + icon come from the registry's
+ * `presentation`; non-url icons fall back to the roof icon.
+ */
+function activateRoofFeatureTool(kind: string): void {
+  const ed = useEditor.getState()
+  ed.setPhase('structure')
+  ed.setStructureLayer('elements')
+  ed.setCatalogCategory(null)
+  ed.setMode('build')
+  ed.setTool(kind as Parameters<typeof ed.setTool>[0])
+}
+
 /**
  * Build tab for the open-source standalone editor — a preset-less replica of
  * the community Build sidebar. Clicking a type activates its raw tool, drawn
@@ -88,11 +111,32 @@ function activatePaintMode(): void {
 export function BuildTab() {
   const activeTool = useEditor((s) => s.tool)
   const mode = useEditor((s) => s.mode)
+  // Which build tile's panel is showing. Roof is the only tile with a panel
+  // (its Features group); others arm a tool and show nothing below.
+  const [selectedTypeId, setSelectedTypeId] = useState<string | null>(null)
+
+  // Read at render time (not module scope): the registry is populated by the
+  // app bootstrap, so enumerating earlier would race it and see no kinds.
+  const roofFeatures = useMemo<RoofFeature[]>(() => {
+    const features: RoofFeature[] = []
+    for (const [kind, def] of nodeRegistry.entries()) {
+      if (def.capabilities.roofAccessory === undefined) continue
+      // Door / window declare `roofAccessory` for the wall-face cut but
+      // already have their own Build tiles — listing them here too
+      // would duplicate the entry under Roof → Features.
+      if (def.capabilities.wallOpeningPlacement) continue
+      const icon = def.presentation?.icon
+      features.push({
+        kind,
+        label: def.presentation?.label ?? kind,
+        iconSrc: icon?.kind === 'url' ? icon.src : ROOF_FEATURE_FALLBACK_ICON,
+      })
+    }
+    return features
+  }, [])
 
   const isTypeActive = (type: BuildType) =>
-    type.mode === 'material-paint'
-      ? mode === 'material-paint'
-      : mode === 'build' && activeTool === type.kind
+    type.mode === 'material-paint' ? mode === 'material-paint' : selectedTypeId === type.id
 
   const handleTypeClick = useCallback((type: BuildType) => {
     if (type.mode === 'material-paint') {
@@ -100,6 +144,7 @@ export function BuildTab() {
     } else if (type.kind) {
       activateBuildTool(type.kind)
     }
+    setSelectedTypeId(type.id)
   }, [])
 
   // On open, land on the first build tool — parity with the community Build
@@ -160,6 +205,51 @@ export function BuildTab() {
         <div className="min-h-0 flex-1 overflow-y-auto">
           <MaterialPaintPanel />
         </div>
+      ) : selectedTypeId === 'roof' && roofFeatures.length > 0 ? (
+        <div className="flex min-h-0 flex-1 flex-col gap-2 overflow-y-auto">
+          <div className="px-0.5 pt-1 font-medium text-muted-foreground text-xs">Features</div>
+          <TooltipProvider delayDuration={0} disableHoverableContent>
+            <div
+              className="grid gap-1.5"
+              style={{ gridTemplateColumns: 'repeat(auto-fill, minmax(56px, 1fr))' }}
+            >
+              {roofFeatures.map((feature) => {
+                const active = mode === 'build' && activeTool === feature.kind
+                return (
+                  <Tooltip key={feature.kind}>
+                    <TooltipTrigger asChild>
+                      <button
+                        className={cn(
+                          'group relative flex aspect-square items-center justify-center rounded-xl p-1 transition-all duration-200',
+                          active
+                            ? 'bg-primary/10 ring-1 ring-primary/50'
+                            : 'bg-muted/40 opacity-70 grayscale hover:bg-muted hover:opacity-100 hover:grayscale-0',
+                        )}
+                        onClick={() => {
+                          triggerSFX('sfx:menu-click')
+                          activateRoofFeatureTool(feature.kind)
+                        }}
+                        onMouseEnter={() => triggerSFX('sfx:menu-hover')}
+                        type="button"
+                      >
+                        <Image
+                          alt={feature.label}
+                          className="size-full object-contain transition-transform duration-200 group-hover:scale-110"
+                          height={48}
+                          src={feature.iconSrc}
+                          width={48}
+                        />
+                      </button>
+                    </TooltipTrigger>
+                    <TooltipContent className="pointer-events-none" side="top">
+                      {feature.label}
+                    </TooltipContent>
+                  </Tooltip>
+                )
+              })}
+            </div>
+          </TooltipProvider>
+        </div>
       ) : null}
     </div>
   )

apps/editor/components/viewer-toolbar.tsx

@@ -40,6 +40,7 @@ import {
 } from 'lucide-react'
 import Image from 'next/image'
 import { type ReactNode, useCallback } from 'react'
+import { flushSync } from 'react-dom'
 import { cn } from '@/lib/utils'
 import { Tooltip, TooltipContent, TooltipTrigger } from './toolbar-tooltip'
 
@@ -49,6 +50,24 @@ const TOOLBAR_CONTAINER =
 const TOOLBAR_BTN =
   'flex w-8 items-center justify-center text-muted-foreground/80 transition-colors hover:bg-white/8 hover:text-foreground/90'
 
+function requestWalkthroughPointerLock() {
+  const canvas = document.querySelector<HTMLCanvasElement>('[data-pascal-viewer-3d] canvas')
+  if (!canvas) return
+
+  if (!canvas.hasAttribute('tabindex')) {
+    canvas.tabIndex = -1
+  }
+  canvas.focus({ preventScroll: true })
+
+  if (document.pointerLockElement === canvas) return
+
+  try {
+    canvas.requestPointerLock?.()
+  } catch {
+    return
+  }
+}
+
 function ToolbarTooltip({ children, label }: { children: ReactNode; label: string }) {
   return (
     <Tooltip>
@@ -441,6 +460,15 @@ function DisplayMenu() {
 function WalkthroughButton() {
   const isFirstPersonMode = useEditor((state) => state.isFirstPersonMode)
   const setFirstPersonMode = useEditor((state) => state.setFirstPersonMode)
+  const handleClick = useCallback(() => {
+    if (isFirstPersonMode) {
+      setFirstPersonMode(false)
+      return
+    }
+
+    flushSync(() => setFirstPersonMode(true))
+    requestWalkthroughPointerLock()
+  }, [isFirstPersonMode, setFirstPersonMode])
 
   return (
     <ToolbarTooltip label="Walkthrough">
@@ -449,7 +477,7 @@ function WalkthroughButton() {
           TOOLBAR_BTN,
           isFirstPersonMode && 'bg-emerald-500/15 text-emerald-400 hover:bg-emerald-500/20',
         )}
-        onClick={() => setFirstPersonMode(!isFirstPersonMode)}
+        onClick={handleClick}
         type="button"
       >
         <Footprints className="h-4 w-4" />

packages/core/src/registry/types.ts

@@ -1205,6 +1205,23 @@ export type PaintEffectiveMaterialArgs = {
  */
 export type RoofAccessoryConfig = {
   buildCut?: (node: AnyNode, hostSegment: AnyNode) => BufferGeometry | null
+  /**
+   * Which segment brushes `buildCut` subtracts from. Wall-face openings
+   * (door / window) cut only the wall brush — subtracting the same box
+   * from the shin / deck slabs is pointless work and creates tangential
+   * / coplanar CSG cases near the gable and shed slopes. Defaults to
+   * all three (skylight / dormer genuinely poke through the deck).
+   */
+  cutScope?: 'all' | 'wall'
+  /**
+   * The kind's own dirty-driven geometry system consumes its dirty
+   * marks (door / window via DoorSystem / WindowSystem, which already
+   * cascade to the host segment through `parentId`). The roof-merge
+   * loop must then leave those marks alone — consuming them would
+   * starve that system whenever it defers a rebuild (mesh not mounted
+   * yet, per-frame rebuild budget exhausted).
+   */
+  dirtyHandledByOwnSystem?: boolean
 }
 
 /**

packages/core/src/schema/index.ts

@@ -108,6 +108,17 @@ export {
   RoofSegmentNode,
   RoofType,
 } from './nodes/roof-segment'
+export type { RoofSegmentWallFace, RoofWallFaceId } from './nodes/roof-segment-walls'
+export {
+  clampRectToRoofWallFace,
+  getMaxRoofRectHeightFromAnchor,
+  getMaxRoofRectWidthFromAnchor,
+  getRoofSegmentWallFace,
+  getRoofSegmentWallFaces,
+  getRoofWallFaceFrame,
+  roofFacePointToSegment,
+  segmentPointToRoofWallFace,
+} from './nodes/roof-segment-walls'
 export { ScanNode } from './nodes/scan'
 export { ShelfNode } from './nodes/shelf'
 export { SiteNode } from './nodes/site'

packages/core/src/schema/nodes/door.ts

@@ -46,6 +46,14 @@ export const DoorNode = BaseNode.extend({
   rotation: z.tuple([z.number(), z.number(), z.number()]).default([0, 0, 0]),
   side: z.enum(['front', 'back']).optional(),
   wallId: z.string().optional(),
+  // Alternative host: a roof-segment's generated wall face (base wall
+  // under the roof or a coplanar gable end). When set, `position` is
+  // FACE-LOCAL — [u along the face, v height, z from the wall mid-plane]
+  // — exactly the wall-child convention; the renderer mounts the node
+  // inside the face frame (`getRoofWallFaceFrame`), which is what makes
+  // hosted children track segment resizes live.
+  roofSegmentId: z.string().optional(),
+  roofFace: z.enum(['front', 'back', 'right', 'left']).optional(),
 
   // Overall dimensions
   width: z.number().default(0.9),

packages/core/src/schema/nodes/item.ts

@@ -135,6 +135,13 @@ export const ItemNode = BaseNode.extend({
   // Wall attachment properties (only used when asset.attachTo is "wall" or "wall-side")
   wallId: z.string().optional(),
   wallT: z.number().optional(), // 0-1 parametric position along wall
+  // Alternative wall host: a roof-segment's generated wall face. When
+  // set, `position` is FACE-LOCAL — [u along the face, v = bottom edge,
+  // z from the wall mid-plane] — exactly the wall-child convention
+  // (ItemSystem's wall-side push applies the same way); the renderer
+  // mounts the node inside the face frame (`getRoofWallFaceFrame`).
+  roofSegmentId: z.string().optional(),
+  roofFace: z.enum(['front', 'back', 'right', 'left']).optional(),
 
   // Denormalized references to collections this node belongs to
   collectionIds: z.array(z.custom<CollectionId>()).optional(),

packages/core/src/schema/nodes/roof-segment-walls.test.ts

@@ -0,0 +1,78 @@
+import { describe, expect, test } from 'bun:test'
+import { RoofSegmentNode } from './roof-segment'
+import {
+  getRoofSegmentWallFace,
+  getRoofWallFaceFrame,
+  roofFacePointToSegment,
+  segmentPointToRoofWallFace,
+} from './roof-segment-walls'
+
+function segment(overrides: Partial<RoofSegmentNode> = {}): RoofSegmentNode {
+  return RoofSegmentNode.parse({
+    id: 'rseg_test',
+    type: 'roof-segment',
+    roofType: 'gable',
+    width: 8,
+    depth: 6,
+    wallHeight: 2.6,
+    wallThickness: 0.1,
+    pitch: 40,
+    ...overrides,
+  })
+}
+
+describe('roof wall face frames', () => {
+  test('frame z = 0 lands on the nominal footprint (wall mid-plane)', () => {
+    const seg = segment()
+    // front face, u at the face middle, v = 1, mid-plane.
+    const point = roofFacePointToSegment(seg, 'front', [(8 + 0.1) / 2, 1, 0])
+    expect(point[0]).toBeCloseTo(0)
+    expect(point[1]).toBeCloseTo(1)
+    expect(point[2]).toBeCloseTo(3) // depth / 2 — the footprint plane
+  })
+
+  test('frame +z is the outward normal on every face', () => {
+    const seg = segment()
+    for (const [faceId, axis, sign] of [
+      ['front', 2, 1],
+      ['back', 2, -1],
+      ['right', 0, 1],
+      ['left', 0, -1],
+    ] as const) {
+      const onPlane = roofFacePointToSegment(seg, faceId, [1, 1, 0])
+      const pushed = roofFacePointToSegment(seg, faceId, [1, 1, 0.5])
+      expect(pushed[axis] - onPlane[axis]).toBeCloseTo(0.5 * sign)
+      // The other horizontal axis is unaffected by the push.
+      const other = axis === 2 ? 0 : 2
+      expect(pushed[other] - onPlane[other]).toBeCloseTo(0)
+    }
+  })
+
+  test('face frame agrees with the hit resolver coordinates', () => {
+    const seg = segment()
+    // A point on the outer surface (z = +thickness/2 off the mid-plane)
+    // must read back with the same u/v and dist ≈ 0 off the outer plane.
+    const segLocal = roofFacePointToSegment(seg, 'right', [2.5, 1.25, 0.05])
+    const { u, v, dist } = segmentPointToRoofWallFace(seg, 'right', segLocal)
+    expect(u).toBeCloseTo(2.5)
+    expect(v).toBeCloseTo(1.25)
+    expect(dist).toBeCloseTo(0)
+  })
+
+  test('resizing the segment moves the frame, not the stored coords', () => {
+    // The core live-tracking property: the same face-local point maps to
+    // the new plane after a depth change — children follow by re-render.
+    const before = roofFacePointToSegment(segment(), 'front', [2, 1, 0])
+    const after = roofFacePointToSegment(segment({ depth: 8 }), 'front', [2, 1, 0])
+    expect(before[2]).toBeCloseTo(3)
+    expect(after[2]).toBeCloseTo(4)
+    expect(after[1]).toBeCloseTo(before[1])
+  })
+
+  test('frame yaw matches the face descriptor yaw', () => {
+    const seg = segment()
+    for (const faceId of ['front', 'back', 'right', 'left'] as const) {
+      expect(getRoofWallFaceFrame(seg, faceId).yaw).toBe(getRoofSegmentWallFace(seg, faceId).yaw)
+    }
+  })
+})

packages/core/src/schema/nodes/roof-segment-walls.ts

@@ -0,0 +1,429 @@
+import type { RoofSegmentNode } from './roof-segment'
+import { getSegmentSlopeFrame } from './roof-segment'
+
+/**
+ * Wall-face math for roof segments — the vertical surfaces a wall-mounted
+ * opening (door / window) can attach to. A segment's generated volume has
+ * four vertical faces; on gable-family roofs the end faces extend past the
+ * eave line into the gable (rect + triangle/pentagon, coplanar with the
+ * base wall). These helpers describe each face as a 2D frame
+ * (`u` along the face, `v` height above the segment base) plus the
+ * placeable profile polygon, so placement tools, renderers, and CSG cut
+ * builders all share one definition of "the wall under the roof".
+ *
+ * The numbers MUST mirror the outer wall volume built by
+ * `getRoofSegmentBrushes` in the viewer's roof system
+ * (`getVol(wallThickness / 2, 0, 0, …)`): the volume is the segment
+ * footprint extended outward by `wallThickness / 2`, which drops the eave
+ * line by `(wallThickness / 2) · tanθ` and raises the ridge by the same
+ * amount so the apex stays at `wallHeight + activeRh`.
+ */
+
+export type RoofWallFaceId = 'front' | 'back' | 'right' | 'left'
+
+export type RoofSegmentWallFace = {
+  id: RoofWallFaceId
+  /** Outward normal in segment-local space. */
+  normal: [number, number, number]
+  /**
+   * Yaw (radians, rotation-y) mapping opening-local +Z to the outward
+   * normal and opening-local +X to the face's +U direction — the same
+   * frame a wall-hosted door/window uses relative to its wall mesh.
+   */
+  yaw: number
+  /** Face length along U. */
+  length: number
+  /**
+   * Placeable region, CCW polygon in face coords. `u ∈ [0, length]`,
+   * `v` is height above the segment base (segment-local Y).
+   */
+  profile: [number, number][]
+}
+
+type SegmentWallInputs = Pick<
+  RoofSegmentNode,
+  'roofType' | 'width' | 'depth' | 'wallHeight' | 'wallThickness' | 'pitch'
+> &
+  Partial<
+    Pick<
+      RoofSegmentNode,
+      | 'gambrelLowerWidthRatio'
+      | 'gambrelLowerHeightRatio'
+      | 'mansardSteepWidthRatio'
+      | 'mansardSteepHeightRatio'
+      | 'dutchHipWidthRatio'
+      | 'dutchHipHeightRatio'
+    >
+  >
+
+type WallVolumeFrame = {
+  /** Outer wall plane extents (footprint + wallThickness). */
+  wV: number
+  dV: number
+  /** Eave height of the outer volume. */
+  eaveY: number
+  /** Ridge/peak height of the outer volume. */
+  peakY: number
+  /** tan(pitch) of the primary slope. */
+  tanTheta: number
+  hasSlope: boolean
+}
+
+function getWallVolumeFrame(node: SegmentWallInputs): WallVolumeFrame {
+  const { activeRh, tanTheta } = getSegmentSlopeFrame(node)
+  const wallThickness = node.wallThickness ?? 0.1
+  const autoDrop = (wallThickness / 2) * tanTheta
+  const wV = Math.max(0.01, node.width + wallThickness)
+  const dV = Math.max(0.01, node.depth + wallThickness)
+  const eaveY = Math.max(0.01, node.wallHeight - autoDrop)
+  let rh = activeRh
+  if (activeRh > 0) {
+    rh = activeRh + autoDrop
+    if (node.roofType === 'shed') rh = activeRh + 2 * autoDrop
+  }
+  return {
+    wV,
+    dV,
+    eaveY,
+    peakY: eaveY + Math.max(0.001, rh),
+    tanTheta,
+    hasSlope: activeRh > 0,
+  }
+}
+
+const FACE_NORMALS: Record<RoofWallFaceId, [number, number, number]> = {
+  front: [0, 0, 1],
+  back: [0, 0, -1],
+  right: [1, 0, 0],
+  left: [-1, 0, 0],
+}
+
+const FACE_YAWS: Record<RoofWallFaceId, number> = {
+  front: 0,
+  back: Math.PI,
+  right: Math.PI / 2,
+  left: -Math.PI / 2,
+}
+
+function rectProfile(length: number, top: number): [number, number][] {
+  return [
+    [0, 0],
+    [length, 0],
+    [length, top],
+    [0, top],
+  ]
+}
+
+function buildFaceProfile(
+  node: SegmentWallInputs,
+  frame: WallVolumeFrame,
+  id: RoofWallFaceId,
+): [number, number][] {
+  const { wV, dV, eaveY, peakY, tanTheta, hasSlope } = frame
+  const isEnd = id === 'right' || id === 'left'
+  const length = isEnd ? dV : wV
+
+  if (!hasSlope) return rectProfile(length, eaveY)
+
+  switch (node.roofType) {
+    case 'gable': {
+      if (!isEnd) return rectProfile(length, eaveY)
+      return [
+        [0, 0],
+        [length, 0],
+        [length, eaveY],
+        [length / 2, peakY],
+        [0, eaveY],
+      ]
+    }
+    case 'gambrel': {
+      if (!isEnd) return rectProfile(length, eaveY)
+      // Kink ring sits at z = ±mz on the nominal footprint (see
+      // getModuleFaces); both end faces are symmetric about u = length/2.
+      const ratio = node.gambrelLowerWidthRatio ?? 0.5
+      const mz = Math.min((node.depth / 2) * ratio, length / 2)
+      const kinkY = eaveY + (length / 2 - mz) * tanTheta
+      return [
+        [0, 0],
+        [length, 0],
+        [length, eaveY],
+        [length / 2 + mz, kinkY],
+        [length / 2, peakY],
+        [length / 2 - mz, kinkY],
+        [0, eaveY],
+      ]
+    }
+    case 'shed': {
+      // Slope falls toward +Z: 'back' is the full-height wall, the end
+      // faces are right trapezoids rising toward the back edge.
+      if (id === 'front') return rectProfile(length, eaveY)
+      if (id === 'back') return rectProfile(length, peakY)
+      if (id === 'right') {
+        return [
+          [0, 0],
+          [length, 0],
+          [length, peakY],
+          [0, eaveY],
+        ]
+      }
+      return [
+        [0, 0],
+        [length, 0],
+        [length, eaveY],
+        [0, peakY],
+      ]
+    }
+    // hip / mansard / dutch slope on every side (dutch gablets are
+    // recessed from the wall plane), so only the base rect is placeable.
+    default:
+      return rectProfile(length, eaveY)
+  }
+}
+
+export function getRoofSegmentWallFace(
+  node: SegmentWallInputs,
+  id: RoofWallFaceId,
+): RoofSegmentWallFace {
+  const frame = getWallVolumeFrame(node)
+  const isEnd = id === 'right' || id === 'left'
+  return {
+    id,
+    normal: FACE_NORMALS[id],
+    yaw: FACE_YAWS[id],
+    length: isEnd ? frame.dV : frame.wV,
+    profile: buildFaceProfile(node, frame, id),
+  }
+}
+
+export function getRoofSegmentWallFaces(node: SegmentWallInputs): RoofSegmentWallFace[] {
+  const frame = getWallVolumeFrame(node)
+  return (['front', 'back', 'right', 'left'] as const).map((id) => ({
+    id,
+    normal: FACE_NORMALS[id],
+    yaw: FACE_YAWS[id],
+    length: id === 'right' || id === 'left' ? frame.dV : frame.wV,
+    profile: buildFaceProfile(node, frame, id),
+  }))
+}
+
+/**
+ * Segment-local point → face coords. `dist` is the signed offset off the
+ * outer wall plane along the face normal (0 = on the plane, positive =
+ * outside the volume).
+ */
+export function segmentPointToRoofWallFace(
+  node: SegmentWallInputs,
+  id: RoofWallFaceId,
+  point: [number, number, number],
+): { u: number; v: number; dist: number } {
+  const { wV, dV } = getWallVolumeFrame(node)
+  const [x, y, z] = point
+  switch (id) {
+    case 'front':
+      return { u: x + wV / 2, v: y, dist: z - dV / 2 }
+    case 'back':
+      return { u: wV / 2 - x, v: y, dist: -z - dV / 2 }
+    case 'right':
+      return { u: dV / 2 - z, v: y, dist: x - wV / 2 }
+    case 'left':
+      return { u: z + dV / 2, v: y, dist: -x - wV / 2 }
+  }
+}
+
+type FaceConstraint = {
+  nu: number
+  nv: number
+  c: number
+}
+
+/**
+ * Inward half-plane constraints of the raw profile polygon (CCW →
+ * interior is to the left of each edge): a point p is inside when
+ * `nu·p.u + nv·p.v ≥ c` for every constraint.
+ */
+function getProfileConstraints(face: RoofSegmentWallFace): FaceConstraint[] {
+  const constraints: FaceConstraint[] = []
+  const pts = face.profile
+  for (let i = 0; i < pts.length; i++) {
+    const a = pts[i]!
+    const b = pts[(i + 1) % pts.length]!
+    const du = b[0] - a[0]
+    const dv = b[1] - a[1]
+    const len = Math.hypot(du, dv)
+    if (len < 1e-9) continue
+    const nu = -dv / len
+    const nv = du / len
+    constraints.push({ nu, nv, c: nu * a[0] + nv * a[1] })
+  }
+  return constraints
+}
+
+/**
+ * Half-plane constraints for the CENTER of a `width × height` rect that
+ * must fit inside the face profile — the raw constraints eroded by the
+ * rect's half-extents projected on each edge normal.
+ */
+function getRectCenterConstraints(
+  face: RoofSegmentWallFace,
+  width: number,
+  height: number,
+): FaceConstraint[] {
+  return getProfileConstraints(face).map(({ nu, nv, c }) => ({
+    nu,
+    nv,
+    c: c + (Math.abs(nu) * width) / 2 + (Math.abs(nv) * height) / 2,
+  }))
+}
+
+/**
+ * The face's render frame in segment-local space: a group placed at
+ * `origin` and yawed by `yaw` maps face coords to segment space —
+ * frame X = U (along the face), frame Y = V (height), frame Z = the
+ * outward normal, with z = 0 on the WALL MID-PLANE. The mid-plane of
+ * the generated wall volume lands exactly on the nominal footprint
+ * (`±width/2` / `±depth/2`), so hosted children use the same position
+ * conventions as wall children (openings at z = 0, wall-side items
+ * pushed +thickness/2 at render time). Renderers derive this from the
+ * live-override-merged segment, which is what makes hosted children
+ * track segment edits live instead of jumping on commit.
+ */
+export function getRoofWallFaceFrame(
+  node: SegmentWallInputs,
+  id: RoofWallFaceId,
+): { origin: [number, number, number]; yaw: number } {
+  const { wV, dV } = getWallVolumeFrame(node)
+  switch (id) {
+    case 'front':
+      return { origin: [-wV / 2, 0, node.depth / 2], yaw: FACE_YAWS.front }
+    case 'back':
+      return { origin: [wV / 2, 0, -node.depth / 2], yaw: FACE_YAWS.back }
+    case 'right':
+      return { origin: [node.width / 2, 0, dV / 2], yaw: FACE_YAWS.right }
+    case 'left':
+      return { origin: [-node.width / 2, 0, -dV / 2], yaw: FACE_YAWS.left }
+  }
+}
+
+/** Face-frame point ([u, v, z-from-mid-plane]) → segment-local point. */
+export function roofFacePointToSegment(
+  node: SegmentWallInputs,
+  id: RoofWallFaceId,
+  point: [number, number, number],
+): [number, number, number] {
+  const { origin, yaw } = getRoofWallFaceFrame(node, id)
+  const cos = Math.cos(yaw)
+  const sin = Math.sin(yaw)
+  const [u, v, z] = point
+  // rotation-y: +x → (cos, 0, -sin), +z → (sin, 0, cos)
+  return [origin[0] + u * cos + z * sin, origin[1] + v, origin[2] - u * sin + z * cos]
+}
+
+/**
+ * Max width of a rect growing from an anchored vertical edge (`anchorU`)
+ * in direction `growSign` (±1 along U) while staying inside the face
+ * profile at the fixed vertical center `vCenter`. Resize-handle limit:
+ * the anchored-edge model matches the handles' apply math (opposite
+ * edge stays put, center re-derives).
+ */
+export function getMaxRoofRectWidthFromAnchor(
+  face: RoofSegmentWallFace,
+  anchorU: number,
+  growSign: number,
+  vCenter: number,
+  height: number,
+): number {
+  let max = Number.POSITIVE_INFINITY
+  for (const { nu, nv, c } of getProfileConstraints(face)) {
+    // Center at anchorU + growSign·w/2, eroded by |nu|·w/2 + |nv|·h/2:
+    // base + k·w ≥ 0 with k ≤ 0 only when growth approaches the edge.
+    const k = (nu * growSign - Math.abs(nu)) / 2
+    if (k >= -1e-9) continue
+    const base = nu * anchorU + nv * vCenter - c - (Math.abs(nv) * height) / 2
+    max = Math.min(max, Math.max(0, base / -k))
+  }
+  return max
+}
+
+/**
+ * Max height of a rect growing from an anchored horizontal edge
+ * (`anchorV`) in direction `growSign` (+1 = bottom anchored, grows up)
+ * while staying inside the face profile at the fixed horizontal center
+ * `uCenter`.
+ */
+export function getMaxRoofRectHeightFromAnchor(
+  face: RoofSegmentWallFace,
+  uCenter: number,
+  width: number,
+  anchorV: number,
+  growSign: number,
+): number {
+  let max = Number.POSITIVE_INFINITY
+  for (const { nu, nv, c } of getProfileConstraints(face)) {
+    const k = (nv * growSign - Math.abs(nv)) / 2
+    if (k >= -1e-9) continue
+    const base = nu * uCenter + nv * anchorV - c - (Math.abs(nu) * width) / 2
+    max = Math.min(max, Math.max(0, base / -k))
+  }
+  return max
+}
+
+const CLAMP_EPSILON = 1e-4
+
+/**
+ * Clamp a rect center so the rect fits inside the face profile.
+ *
+ * - `lockV: true` (doors): `v` is fixed; only `u` slides. Returns null
+ *   when no `u` keeps the rect inside at that height.
+ * - otherwise (windows): the center is projected into the eroded convex
+ *   region (cyclic projection — profiles are convex by construction).
+ *
+ * Returns null when the rect cannot fit anywhere on the face.
+ */
+export function clampRectToRoofWallFace(
+  face: RoofSegmentWallFace,
+  u: number,
+  v: number,
+  width: number,
+  height: number,
+  opts?: { lockV?: boolean },
+): { u: number; v: number } | null {
+  const constraints = getRectCenterConstraints(face, width, height)
+  if (constraints.length < 3) return null
+
+  if (opts?.lockV) {
+    let lo = Number.NEGATIVE_INFINITY
+    let hi = Number.POSITIVE_INFINITY
+    for (const { nu, nv, c } of constraints) {
+      const rhs = c - nv * v
+      if (Math.abs(nu) < 1e-9) {
+        if (rhs > CLAMP_EPSILON) return null
+        continue
+      }
+      if (nu > 0) lo = Math.max(lo, rhs / nu)
+      else hi = Math.min(hi, rhs / nu)
+    }
+    if (lo > hi + CLAMP_EPSILON) return null
+    return { u: Math.min(Math.max(u, lo), hi), v }
+  }
+
+  let pu = u
+  let pv = v
+  for (let iter = 0; iter < 32; iter++) {
+    let worst: FaceConstraint | null = null
+    let worstViolation = CLAMP_EPSILON
+    for (const constraint of constraints) {
+      const violation = constraint.c - (constraint.nu * pu + constraint.nv * pv)
+      if (violation > worstViolation) {
+        worstViolation = violation
+        worst = constraint
+      }
+    }
+    if (!worst) return { u: pu, v: pv }
+    pu += worst.nu * worstViolation
+    pv += worst.nv * worstViolation
+  }
+  for (const { nu, nv, c } of constraints) {
+    if (nu * pu + nv * pv < c - 1e-3) return null
+  }
+  return { u: pu, v: pv }
+}

packages/core/src/schema/nodes/window.ts

@@ -28,6 +28,14 @@ export const WindowNode = BaseNode.extend({
 
   // Wall reference
   wallId: z.string().optional(),
+  // Alternative host: a roof-segment's generated wall face (base wall
+  // under the roof or a coplanar gable end). When set, `position` is
+  // FACE-LOCAL — [u along the face, v height, z from the wall mid-plane]
+  // — exactly the wall-child convention; the renderer mounts the node
+  // inside the face frame (`getRoofWallFaceFrame`), which is what makes
+  // hosted children track segment resizes live.
+  roofSegmentId: z.string().optional(),
+  roofFace: z.enum(['front', 'back', 'right', 'left']).optional(),
 
   // Overall dimensions
   width: z.number().default(1.5),

packages/core/src/store/use-scene.ts

@@ -14,6 +14,7 @@ import {
   type RoofSegmentNode,
   type RoofType,
 } from '../schema/nodes/roof-segment'
+import { segmentPointToRoofWallFace } from '../schema/nodes/roof-segment-walls'
 import { ShelfNode as ShelfNodeSchema } from '../schema/nodes/shelf'
 import { SiteNode } from '../schema/nodes/site'
 import { StairNode as StairNodeSchema } from '../schema/nodes/stair'
@@ -539,6 +540,55 @@ function migrateNodes(nodes: Record<string, any>): Record<string, AnyNode> {
       patchedNodes[id] = { ...node, children: [] } as AnyNode
     }
 
+    // Roof-hosted wall children (door / window / item) originally stored
+    // SEGMENT-LOCAL positions with the face yaw in rotation[1]; the
+    // format moved to explicit `roofFace` + FACE-LOCAL coords so the
+    // renderer's face frame can track segment edits live. Convert in
+    // place: face from the old cardinal yaw, u/v from the outer-plane
+    // projection, z re-based from the outer plane to the wall mid-plane.
+    if (
+      (node.type === 'door' || node.type === 'window' || node.type === 'item') &&
+      typeof (node as { roofSegmentId?: unknown }).roofSegmentId === 'string' &&
+      (node as { roofFace?: unknown }).roofFace === undefined
+    ) {
+      const current = patchedNodes[id] as AnyNode & {
+        roofSegmentId: string
+        position: [number, number, number]
+        rotation: [number, number, number]
+      }
+      const segment = patchedNodes[current.roofSegmentId] as
+        | (AnyNode & { wallThickness?: number })
+        | undefined
+      if (segment?.type === 'roof-segment') {
+        const tau = Math.PI * 2
+        const yaw = (((current.rotation?.[1] ?? 0) % tau) + tau) % tau
+        const eps = 1e-3
+        const face =
+          yaw < eps || tau - yaw < eps
+            ? ('front' as const)
+            : Math.abs(yaw - Math.PI) < eps
+              ? ('back' as const)
+              : Math.abs(yaw - Math.PI / 2) < eps
+                ? ('right' as const)
+                : Math.abs(yaw - (3 * Math.PI) / 2) < eps
+                  ? ('left' as const)
+                  : null
+        if (face) {
+          const { u, v, dist } = segmentPointToRoofWallFace(
+            segment as never,
+            face,
+            current.position,
+          )
+          patchedNodes[id] = {
+            ...current,
+            roofFace: face,
+            position: [u, v, dist + (segment.wallThickness ?? 0.1) / 2],
+            rotation: [0, 0, 0],
+          } as AnyNode
+        }
+      }
+    }
+
     if (node.type === 'roof') {
       patchedNodes[id] = migrateRoofSurfaceMaterials(patchedNodes[id])
     }

packages/core/src/utils/clone-scene-graph.ts

@@ -76,6 +76,13 @@ export function cloneSceneGraph(sceneGraph: SceneGraph): SceneGraph {
         | undefined
     }
 
+    // Remap roofSegmentId (doors/windows/items hosted on roof wall faces)
+    if ('roofSegmentId' in clonedNode && typeof clonedNode.roofSegmentId === 'string') {
+      ;(clonedNode as Record<string, unknown>).roofSegmentId = idMap.get(
+        clonedNode.roofSegmentId,
+      ) as string | undefined
+    }
+
     clonedNodes[newId] = clonedNode
   }
 
@@ -220,6 +227,12 @@ export function cloneLevelSubtree(
       ;(cloned as Record<string, unknown>).wallId = idMap.get(cloned.wallId) ?? cloned.wallId
     }
 
+    // Remap roofSegmentId (doors/windows/items hosted on roof wall faces)
+    if ('roofSegmentId' in cloned && typeof cloned.roofSegmentId === 'string') {
+      ;(cloned as Record<string, unknown>).roofSegmentId =
+        idMap.get(cloned.roofSegmentId) ?? cloned.roofSegmentId
+    }
+
     clonedNodes.push(cloned)
   }
 

packages/editor/src/components/editor-2d/renderers/floorplan-registry-layer.tsx

@@ -19,7 +19,6 @@ import {
   useLiveTransforms,
   useScene,
 } from '@pascal-app/core'
-import { useAlignmentGuides } from '@pascal-app/editor'
 import { useViewer } from '@pascal-app/viewer'
 import {
   memo,
@@ -31,7 +30,9 @@ import {
   useState,
 } from 'react'
 import { sfxEmitter } from '../../../lib/sfx-bus'
+import { clearSurfacePlanSnapFeedback } from '../../../lib/surface-plan-snap'
 import useEditor from '../../../store/use-editor'
+import { suppressBoxSelectForPointer } from '../../tools/select/box-select-state'
 import { useFloorplanRender } from '../floorplan-render-context'
 import { FloorplanGeometryRenderer } from './floorplan-geometry-renderer'
 
@@ -493,6 +494,7 @@ export const FloorplanRegistryLayer = memo(function FloorplanRegistryLayer() {
 
       event.preventDefault()
       event.stopPropagation()
+      suppressBoxSelectForPointer(event)
 
       const session = handler.start({
         node,
@@ -603,6 +605,7 @@ export const FloorplanRegistryLayer = memo(function FloorplanRegistryLayer() {
         }
         drag.session.commit()
         sfxEmitter.emit('sfx:structure-build')
+        clearSurfacePlanSnapFeedback()
         dragRef.current = null
         setActiveDragId(null)
         setRotationOverlay(null)
@@ -654,6 +657,7 @@ export const FloorplanRegistryLayer = memo(function FloorplanRegistryLayer() {
         for (const id of drag.session.affectedIds) overrides.clear(id)
       }
 
+      clearSurfacePlanSnapFeedback()
       dragRef.current = null
       setActiveDragId(null)
       setRotationOverlay(null)
@@ -672,7 +676,7 @@ export const FloorplanRegistryLayer = memo(function FloorplanRegistryLayer() {
       // Affordances that publish Figma alignment guides during `apply`
       // (fence endpoint) leave them in the store on cancel — `canCommit`
       // (the pointer-up clear) never runs on a cancel.
-      useAlignmentGuides.getState().clear()
+      clearSurfacePlanSnapFeedback()
       // Drop any live overrides the session may have published. No-op
       // for affordances whose `apply()` writes straight to scene; the
       // override-routed sessions (wall endpoint, wall curve) rely on
@@ -707,7 +711,7 @@ export const FloorplanRegistryLayer = memo(function FloorplanRegistryLayer() {
         dragRef.current = null
       }
       // Clear any alignment guide a session left behind on mid-drag unmount.
-      useAlignmentGuides.getState().clear()
+      clearSurfacePlanSnapFeedback()
     }
   }, [])
 
@@ -767,6 +771,7 @@ export const FloorplanRegistryLayer = memo(function FloorplanRegistryLayer() {
           if (!node) return
           event.preventDefault()
           event.stopPropagation()
+          suppressBoxSelectForPointer(event)
           sfxEmitter.emit('sfx:item-pick')
           setMovingNode(node as never)
         }}

packages/editor/src/components/editor/first-person-controls.tsx

@@ -64,7 +64,7 @@ import {
   type FirstPersonColliderWorld,
   type FirstPersonSpawn,
 } from './first-person/build-collider-world'
-import type { BVHEcctrlApi } from './first-person/bvh-ecctrl'
+import type { BVHEcctrlApi, MovementInput } from './first-person/bvh-ecctrl'
 import BVHEcctrl from './first-person/bvh-ecctrl'
 
 const CAMERA_EYE_OFFSET = 0.45
@@ -78,7 +78,11 @@ const ELEVATOR_COLLIDER_FLOOR_THICKNESS = 0.08
 const ELEVATOR_COLLIDER_DOOR_DEPTH = 0.12
 const ELEVATOR_ENTRY_DOOR_OPEN_THRESHOLD = 0.72
 const DEFAULT_ELEVATOR_LEVEL_HEIGHT = 2.5
-const keyboardMap = [
+const VOID_FALL_RESPAWN_DEPTH = 12
+
+type MovementKeyName = Exclude<keyof MovementInput, 'joystick'>
+
+const movementKeyboardBindings: Array<{ name: MovementKeyName; keys: string[] }> = [
   { name: 'forward', keys: ['ArrowUp', 'KeyW'] },
   { name: 'backward', keys: ['ArrowDown', 'KeyS'] },
   { name: 'leftward', keys: ['ArrowLeft', 'KeyA'] },
@@ -86,6 +90,36 @@ const keyboardMap = [
   { name: 'jump', keys: ['Space'] },
   { name: 'run', keys: ['ShiftLeft', 'ShiftRight'] },
 ]
+const keyboardMap = movementKeyboardBindings
+const movementKeyToName = new Map<string, MovementKeyName>(
+  movementKeyboardBindings.flatMap(({ name, keys }) => keys.map((key) => [key, name] as const)),
+)
+
+const inactiveMovementInput: MovementInput = {
+  backward: false,
+  forward: false,
+  jump: false,
+  leftward: false,
+  rightward: false,
+  run: false,
+}
+
+function getMovementInputForKey(code: string, active: boolean): MovementInput | null {
+  const name = movementKeyToName.get(code)
+  return name ? ({ [name]: active } as MovementInput) : null
+}
+
+function focusFirstPersonCanvas(canvas: HTMLCanvasElement) {
+  const activeElement = document.activeElement
+  if (activeElement instanceof HTMLElement && !canvas.contains(activeElement)) {
+    activeElement.blur()
+  }
+
+  if (!canvas.hasAttribute('tabindex')) {
+    canvas.tabIndex = -1
+  }
+  canvas.focus({ preventScroll: true })
+}
 
 const cameraOffset = new Vector3(0, CAMERA_EYE_OFFSET, 0)
 const cameraEuler = new Euler(0, 0, 0, 'YXZ')
@@ -535,6 +569,8 @@ export const FirstPersonControls = () => {
   const selectedLevelId = useViewer((state) => state.selection.levelId)
   const placedSpawnNode = useScene((state) => resolvePlacedSpawnNode(state.nodes, selectedLevelId))
   const controllerRef = useRef<BVHEcctrlApi | null>(null)
+  const movementInputRef = useRef<MovementInput>({ ...inactiveMovementInput })
+  const hadPointerLockRef = useRef(false)
   const yawRef = useRef(0)
   const pitchRef = useRef(0)
   const interactableTargetRef = useRef<FirstPersonInteractableTarget | null>(null)
@@ -577,6 +613,13 @@ export const FirstPersonControls = () => {
     setIsElevatorRideLocked(locked)
   }, [])
 
+  const setControllerApi = useCallback((api: BVHEcctrlApi | null) => {
+    controllerRef.current = api
+    if (api) {
+      api.setMovement(movementInputRef.current)
+    }
+  }, [])
+
   const resolveInteractableDoorId = useCallback((): AnyNodeId | null => {
     const nodes = useScene.getState().nodes
     camera.updateMatrixWorld(true)
@@ -915,6 +958,14 @@ export const FirstPersonControls = () => {
     })
   }, [camera, controllerStart, placedSpawn, world])
 
+  useEffect(() => {
+    const canvas = gl.domElement
+    focusFirstPersonCanvas(canvas)
+
+    const frame = window.requestAnimationFrame(() => focusFirstPersonCanvas(canvas))
+    return () => window.cancelAnimationFrame(frame)
+  }, [gl])
+
   useEffect(() => {
     const canvas = gl.domElement
     const handleMouseMove = (e: MouseEvent) => {
@@ -945,14 +996,29 @@ export const FirstPersonControls = () => {
       toggleInteractableTarget()
     }
 
+    const handlePointerLockChange = () => {
+      const isLocked = document.pointerLockElement === canvas
+      if (isLocked) {
+        hadPointerLockRef.current = true
+        return
+      }
+
+      if (hadPointerLockRef.current && useEditor.getState().isFirstPersonMode) {
+        useEditor.getState().setFirstPersonMode(false)
+      }
+    }
+
+    handlePointerLockChange()
     document.addEventListener('mousemove', handleMouseMove)
     document.addEventListener('click', handleClick)
     document.addEventListener('mousedown', handleMouseDown, true)
+    document.addEventListener('pointerlockchange', handlePointerLockChange)
 
     return () => {
       document.removeEventListener('mousemove', handleMouseMove)
       document.removeEventListener('click', handleClick)
       document.removeEventListener('mousedown', handleMouseDown, true)
+      document.removeEventListener('pointerlockchange', handlePointerLockChange)
       if (document.pointerLockElement === canvas) {
         document.exitPointerLock()
       }
@@ -962,7 +1028,24 @@ export const FirstPersonControls = () => {
   useEffect(() => {
     const canvas = gl.domElement
 
+    const applyMovementKey = (event: KeyboardEvent, active: boolean) => {
+      if (event.target instanceof HTMLInputElement || event.target instanceof HTMLTextAreaElement) {
+        return false
+      }
+
+      const movement = getMovementInputForKey(event.code, active)
+      if (!movement) return false
+
+      event.preventDefault()
+      Object.assign(movementInputRef.current, movement)
+      controllerRef.current?.setMovement(movement)
+      return true
+    }
+
     const handleKeyDown = (event: KeyboardEvent) => {
+      const handledMovement = applyMovementKey(event, true)
+      if (handledMovement) return
+
       if (event.target instanceof HTMLInputElement || event.target instanceof HTMLTextAreaElement) {
         return
       }
@@ -985,9 +1068,15 @@ export const FirstPersonControls = () => {
       }
     }
 
+    const handleKeyUp = (event: KeyboardEvent) => {
+      applyMovementKey(event, false)
+    }
+
     document.addEventListener('keydown', handleKeyDown, true)
+    document.addEventListener('keyup', handleKeyUp, true)
     return () => {
       document.removeEventListener('keydown', handleKeyDown, true)
+      document.removeEventListener('keyup', handleKeyUp, true)
     }
   }, [closeInteractableTarget, gl, toggleInteractableTarget])
 
@@ -1217,6 +1306,29 @@ export const FirstPersonControls = () => {
     if (!controllerRef.current?.group) return
 
     const group = controllerRef.current.group
+
+    // The site ground collider is effectively unbounded, but scenes without a
+    // site node only have finite fallback floors — if the controller still ends
+    // up below every collider it can never land, so put it back at the spawn.
+    // Prefer the live spawn node over the mount-time start position so a spawn
+    // moved mid-walkthrough doesn't respawn the player at stale coordinates.
+    const worldBounds = worldRef.current?.bounds
+    if (worldBounds && group.position.y < worldBounds.min.y - VOID_FALL_RESPAWN_DEPTH) {
+      const respawnPosition = placedSpawn
+        ? [
+            placedSpawn.position[0],
+            placedSpawn.position[1] - CONTROLLER_CENTER_FROM_EYE,
+            placedSpawn.position[2],
+          ]
+        : controllerStart?.position
+      if (respawnPosition) {
+        group.position.set(respawnPosition[0]!, respawnPosition[1]!, respawnPosition[2]!)
+        controllerRef.current.resetLinVel()
+        ridingElevatorRef.current = null
+        setElevatorRideLocked(false)
+      }
+    }
+
     group.rotation.y = 0
     camera.position.copy(group.position).add(cameraOffset)
     cameraEuler.set(pitchRef.current, yawRef.current, 0, 'YXZ')
@@ -1284,7 +1396,7 @@ export const FirstPersonControls = () => {
             maxWalkSpeed={4}
             paused={isElevatorRideLocked}
             position={controllerStart.position}
-            ref={controllerRef}
+            ref={setControllerApi}
           />
         </KeyboardControls>
       )}

packages/editor/src/components/editor/first-person/build-collider-world.test.ts

@@ -105,6 +105,36 @@ describe('buildFirstPersonColliderWorldFromRegistry', () => {
     world?.dispose()
   })
 
+  test('skips meshes hidden by an invisible ancestor (stale roof segment CSG)', () => {
+    registerColliderDefinition('column', ColumnNode, 'structure')
+
+    // Mirror the roof's segments-wrapper shape: the registered mesh's own
+    // visible flag stays true while a hidden wrapper hides it at render
+    // time. The collider must match the render, not the own-flag.
+    const column = ColumnNode.parse({ id: 'column_test' })
+    const visibleColumn = ColumnNode.parse({ id: 'column_visible', position: [3, 0, 0] })
+    setSceneNodes([column, visibleColumn])
+
+    const wrapper = new Group()
+    wrapper.visible = false
+    const hiddenMesh = new Mesh(new BoxGeometry(10, 2, 10), new MeshBasicMaterial())
+    wrapper.add(hiddenMesh)
+    wrapper.updateMatrixWorld(true)
+    sceneRegistry.nodes.set(column.id, hiddenMesh)
+    sceneRegistry.byType[column.type]!.add(column.id)
+
+    mountNode(visibleColumn, [1, 2, 1], [3, 1, 0])
+
+    const world = buildFirstPersonColliderWorldFromRegistry()
+
+    expect(world).not.toBeNull()
+    // Bounds reflect only the visible 1×1 column at x = 3; the 10×10 mesh
+    // under the hidden wrapper contributed no geometry.
+    expect(world?.bounds?.min.x).toBeCloseTo(2.5)
+    expect(world?.bounds?.max.x).toBeCloseTo(3.5)
+    world?.dispose()
+  })
+
   test('leaves elevators to their dedicated dynamic collider meshes', () => {
     registerColliderDefinition('elevator', ElevatorNode, 'structure')
 
@@ -141,9 +171,12 @@ describe('buildFirstPersonColliderWorldFromRegistry', () => {
     // Ground slab sits just below the site ground plane (y = 0).
     expect(world?.bounds?.min.y).toBeCloseTo(-0.08)
     expect(world?.bounds?.max.y).toBeCloseTo(0)
-    // Default site footprint falls back to the 30 m minimum size.
-    expect(world?.bounds?.min.x).toBeCloseTo(-15)
-    expect(world?.bounds?.max.x).toBeCloseTo(15)
+    // The ground collider extends far past the site polygon so stepping out of
+    // the site boundary never drops the player below the ground plane.
+    expect(world?.bounds?.min.x).toBeCloseTo(-1000)
+    expect(world?.bounds?.max.x).toBeCloseTo(1000)
+    expect(world?.bounds?.min.z).toBeCloseTo(-1000)
+    expect(world?.bounds?.max.z).toBeCloseTo(1000)
     world?.dispose()
   })
 })

packages/editor/src/components/editor/first-person/build-collider-world.ts

@@ -27,6 +27,7 @@ const OPERATION_DOOR_COLLIDER_OPEN_THRESHOLD = 0.85
 const LEVEL_FALLBACK_FLOOR_THICKNESS = 0.08
 const LEVEL_FALLBACK_FLOOR_PADDING = 2
 const LEVEL_FALLBACK_FLOOR_MIN_SIZE = 30
+const SITE_GROUND_COLLIDER_MIN_SIZE = 2000
 
 export const FIRST_PERSON_SPAWN_EYE_HEIGHT = SPAWN_EYE_HEIGHT
 
@@ -49,6 +50,22 @@ function isMesh(object: THREE.Object3D): object is THREE.Mesh {
   return 'isMesh' in object && (object as THREE.Mesh).isMesh
 }
 
+// Renderer-effective visibility: an invisible ancestor hides the whole
+// subtree at render time even when the object's own flag is true. The
+// collider world must match what's rendered — the roof keeps stale,
+// UNCUT per-segment CSG inside its hidden `segments-wrapper` (full-edit
+// exit hides the wrapper without stripping geometry), and cloning those
+// meshes would block the walkthrough player at openings the visible
+// merged shell has cut through.
+function isEffectivelyVisible(object: THREE.Object3D) {
+  let current: THREE.Object3D | null = object
+  while (current) {
+    if (!current.visible) return false
+    current = current.parent
+  }
+  return true
+}
+
 function isColliderMaterialVisible(material: THREE.Material | THREE.Material[]) {
   return Array.isArray(material) ? material.some((entry) => entry.visible) : material.visible
 }
@@ -129,8 +146,10 @@ function collectLevelFallbackFloorGeometries(nodes: SceneNodes) {
 // a dedicated collider, a spawn on the bare ground (no slab, or not parented to
 // a level that triggers the per-level fallback) has no floor to stand on and the
 // walkthrough player falls through. Derive a thin ground slab from node data (not
-// the rendered mesh) so it exists regardless of geometry-mount timing, sized to
-// cover the whole scene footprint at the site's ground plane.
+// the rendered mesh) so it exists regardless of geometry-mount timing. The slab
+// is effectively unbounded (not sized to the site polygon): the ground plane must
+// keep holding the player up even after they step past the site boundary,
+// otherwise they fall below the ground plane into the void.
 function createSiteGroundColliderGeometry(site: SiteNode, nodes: SceneNodes) {
   if (site.visible === false) return null
 
@@ -142,11 +161,11 @@ function createSiteGroundColliderGeometry(site: SiteNode, nodes: SceneNodes) {
   const [boundsWidth, boundsDepth] = bounds?.size ?? [0, 0]
   const width = Math.max(
     boundsWidth + LEVEL_FALLBACK_FLOOR_PADDING * 2,
-    LEVEL_FALLBACK_FLOOR_MIN_SIZE,
+    SITE_GROUND_COLLIDER_MIN_SIZE,
   )
   const depth = Math.max(
     boundsDepth + LEVEL_FALLBACK_FLOOR_PADDING * 2,
-    LEVEL_FALLBACK_FLOOR_MIN_SIZE,
+    SITE_GROUND_COLLIDER_MIN_SIZE,
   )
 
   const geometry = createBoxColliderGeometry(width, LEVEL_FALLBACK_FLOOR_THICKNESS, depth)
@@ -316,9 +335,12 @@ function collectColliderGeometriesFromNode(
     if (visitedMeshes.has(object)) return
     visitedMeshes.add(object)
 
+    // Prune hidden subtrees — children of an invisible group never render,
+    // so they must not collide either (see isEffectivelyVisible).
+    if (!object.visible) return
+
     if (
       isMesh(object) &&
-      object.visible &&
       isColliderMaterialVisible(object.material) &&
       !SKIPPED_MESH_NAMES.has(object.name)
     ) {
@@ -361,6 +383,11 @@ export function buildFirstPersonColliderWorldFromRegistry(): FirstPersonCollider
     const root = sceneRegistry.nodes.get(nodeId)
     if (!root) continue
 
+    // Registered objects can sit inside a hidden wrapper (roof segments
+    // under `segments-wrapper`) — the per-node traversal starts AT the
+    // object, so the ancestor chain must be checked here.
+    if (!isEffectivelyVisible(root)) continue
+
     if (node.type === 'door') {
       const doorGeometry = createDoorLeafColliderGeometry(root, node)
       if (doorGeometry) {

packages/editor/src/components/editor/floating-action-menu.tsx

@@ -10,6 +10,8 @@ import {
   ElevatorNode,
   FenceNode,
   generateId,
+  getActiveRoofHeight,
+  getEffectiveNode,
   getWallCurveLength,
   getWallThickness,
   ItemNode,
@@ -111,6 +113,49 @@ function getMenuYOffset(node: AnyNode | null): number {
   return (MENU_Y_OFFSETS[node.type] ?? MENU_Y_OFFSET_DEFAULT) + EXTRA_MENU_LIFT
 }
 
+function getAttributeVersion(
+  attribute: THREE.BufferAttribute | THREE.InterleavedBufferAttribute | null | undefined,
+): number {
+  return attribute && 'version' in attribute && typeof attribute.version === 'number'
+    ? attribute.version
+    : 0
+}
+
+function getObjectGeometryKey(object: THREE.Object3D): string {
+  const parts: string[] = []
+  object.traverse((child) => {
+    const geometry = (child as Partial<THREE.Mesh>).geometry
+    if (!geometry) return
+
+    parts.push(
+      [
+        geometry.id,
+        getAttributeVersion(geometry.getAttribute('position')),
+        getAttributeVersion(geometry.getIndex()),
+      ].join(':'),
+    )
+  })
+  return parts.join('|')
+}
+
+function setNodeDerivedMenuAnchor(
+  node: AnyNode,
+  object: THREE.Object3D,
+  target: THREE.Vector3,
+): boolean {
+  if (node.type !== 'roof-segment') return false
+
+  const visualTop =
+    node.wallHeight +
+    getActiveRoofHeight(node) +
+    Math.max(0, node.deckThickness ?? 0) +
+    Math.max(0, node.shingleThickness ?? 0)
+
+  target.set(0, visualTop, 0).applyMatrix4(object.matrixWorld)
+  target.y += getMenuYOffset(node)
+  return true
+}
+
 // Fence schema defaults — mirror packages/nodes/src/fence/definition.ts so the
 // pill reads sensibly before an explicit height / thickness is set.
 const FENCE_DEFAULT_HEIGHT = 1.8
@@ -171,9 +216,14 @@ export function FloatingActionMenu() {
   const anchorRef = useRef(new THREE.Vector3())
   const hasAnchorRef = useRef(false)
   const lastMatrixRef = useRef(new THREE.Matrix4())
-  const lastAnchorKeyRef = useRef<{ id: string | null; node: AnyNode | null }>({
+  const lastAnchorKeyRef = useRef<{
+    id: string | null
+    node: AnyNode | null
+    geometryKey: string | null
+  }>({
     id: null,
     node: null,
+    geometryKey: null,
   })
 
   // Only show for single selection of specific types
@@ -218,7 +268,7 @@ export function FloatingActionMenu() {
   })
 
   useFrame((state) => {
-    if (!(selectedId && isValidType && groupRef.current)) return
+    if (!(selectedId && node && isValidType && groupRef.current)) return
 
     // Scale the HTML menu with camera zoom (ortho) or inverse distance
     // (perspective) so it feels anchored to the world, clamped on both ends
@@ -253,6 +303,8 @@ export function FloatingActionMenu() {
 
     const obj = sceneRegistry.nodes.get(selectedId)
     if (obj) {
+      obj.updateWorldMatrix(true, false)
+
       // Recompute the anchor only when the object genuinely changes —
       // reselected, moved (its own world matrix changed), or resized
       // (a fresh store node on commit, or a live override / handle drag
@@ -261,21 +313,28 @@ export function FloatingActionMenu() {
       // holds still.
       const overrideActive = useLiveNodeOverrides.getState().overrides.get(selectedId) != null
       const dragActive = activeHandleDrag?.nodeId === selectedId
+      const effectiveNode = getEffectiveNode(node)
+      const geometryKey = getObjectGeometryKey(obj)
       const selectionChanged =
         lastAnchorKeyRef.current.id !== selectedId || lastAnchorKeyRef.current.node !== node
       const matrixChanged = !lastMatrixRef.current.equals(obj.matrixWorld)
+      const geometryChanged = lastAnchorKeyRef.current.geometryKey !== geometryKey
 
-      if (selectionChanged || matrixChanged || overrideActive || dragActive) {
+      if (selectionChanged || matrixChanged || geometryChanged || overrideActive || dragActive) {
+        if (!setNodeDerivedMenuAnchor(effectiveNode, obj, anchorRef.current)) {
           const box = new THREE.Box3().setFromObject(obj)
           if (!box.isEmpty()) {
             const center = box.getCenter(new THREE.Vector3())
             // Position above the object. Per-type offsets clear each kind's
             // in-world chrome (height-resize arrows, measurement labels).
-          anchorRef.current.set(center.x, box.max.y + getMenuYOffset(node), center.z)
+            anchorRef.current.set(center.x, box.max.y + getMenuYOffset(effectiveNode), center.z)
+            hasAnchorRef.current = true
+          }
+        } else {
           hasAnchorRef.current = true
         }
         lastMatrixRef.current.copy(obj.matrixWorld)
-        lastAnchorKeyRef.current = { id: selectedId, node }
+        lastAnchorKeyRef.current = { id: selectedId, node, geometryKey }
       }
 
       if (hasAnchorRef.current) {

packages/editor/src/components/editor/floorplan-panel.tsx

@@ -64,6 +64,7 @@ import {
 import { createPortal } from 'react-dom'
 import { Vector3 } from 'three'
 import { useShallow } from 'zustand/react/shallow'
+import { resolveCeilingPlanPointSnap } from '../../lib/ceiling-plan-snap'
 import {
   alignFloorplanDraftPoint,
   buildFloorplanItemEntry,
@@ -77,6 +78,7 @@ import { guideEmitter } from '../../lib/guide-events'
 import { formatLinearMeasurement, linearUnitToMeters } from '../../lib/measurements'
 import { sfxEmitter } from '../../lib/sfx-bus'
 import { SITE_BOUNDARY_DRAG_LABEL } from '../../lib/site-boundary'
+import { resolveSlabPlanPointSnap } from '../../lib/slab-plan-snap'
 import { cn } from '../../lib/utils'
 import { snapBuildingLocalToWorldGrid } from '../../lib/world-grid-snap'
 import type { GuideUiState, NavigationSyncPose } from '../../store/use-editor'
@@ -8429,17 +8431,22 @@ export function FloorplanPanel({
 
       if (isCeilingBuildActive) {
         // Polygon vertex: grid (snapToHalf) + optional 45° angle snap from
-        // the previous vertex. Alignment runs only when angle snap is OFF
-        // (first vertex, or Shift held) — when the angle is being locked,
-        // pulling the vertex sideways would break it.
+        // the previous vertex. Wall magnetic snap may still win, while
+        // generic alignment runs only when angle snap is OFF (first vertex,
+        // or Shift held) so it does not pull a locked angle sideways.
         const angleSnap = ceilingDraftPoints.length > 0 && !shiftPressed
-        let snappedPoint = snapPolygonDraftPoint({
+        const fallbackPoint = snapPolygonDraftPoint({
           point: planPoint,
           start: ceilingDraftPoints[ceilingDraftPoints.length - 1],
           angleSnap,
         })
-        if (angleSnap) useAlignmentGuides.getState().clear()
-        else snappedPoint = alignFloorplanDraftPoint(snappedPoint, { bypass: event.altKey })
+        const snappedPoint = resolveCeilingPlanPointSnap({
+          rawPoint: planPoint,
+          fallbackPoint,
+          levelId,
+          altKey: event.altKey,
+          align: !angleSnap,
+        }).point
 
         emitFloorplanGridEvent('move', snappedPoint, event)
         setCursorPoint((previousPoint) =>
@@ -8505,13 +8512,25 @@ export function FloorplanPanel({
       // moves (the catch-all would otherwise swallow the move event).
       if (isPolygonBuildActive) {
         const angleSnap = activePolygonDraftPoints.length > 0 && !shiftPressed
-        let snappedPoint = snapPolygonDraftPoint({
+        const fallbackPoint = snapPolygonDraftPoint({
           point: planPoint,
           start: activePolygonDraftPoints[activePolygonDraftPoints.length - 1],
           angleSnap,
         })
-        if (angleSnap) useAlignmentGuides.getState().clear()
-        else snappedPoint = alignFloorplanDraftPoint(snappedPoint, { bypass: event.altKey })
+        let snappedPoint = fallbackPoint
+        if (isSlabBuildActive) {
+          snappedPoint = resolveSlabPlanPointSnap({
+            rawPoint: planPoint,
+            fallbackPoint,
+            levelId,
+            altKey: event.altKey,
+            align: !angleSnap,
+          }).point
+        } else if (angleSnap) {
+          useAlignmentGuides.getState().clear()
+        } else {
+          snappedPoint = alignFloorplanDraftPoint(fallbackPoint, { bypass: event.altKey })
+        }
 
         // Emit `grid:move` so the registry-driven slab tool also tracks
         // the cursor (its 3D preview needs it).
@@ -8679,7 +8698,9 @@ export function FloorplanPanel({
       isOpeningPlacementActive,
       isPolygonBuildActive,
       isRoofBuildActive,
+      isSlabBuildActive,
       isWallBuildActive,
+      levelId,
       publishFloorplanNavigationPose,
       smoothFloorplanNavigationView,
       referenceScaleDraft,
@@ -8936,8 +8957,10 @@ export function FloorplanPanel({
     isOpeningPlacementActive,
     isPolygonBuildActive,
     isRoofBuildActive,
+    isSlabBuildActive,
     isWallBuildActive,
     isZoneBuildActive,
+    levelId,
     roofDraftStart,
     setCursorPoint,
     setFenceDraftEnd,
@@ -9114,24 +9137,39 @@ export function FloorplanPanel({
         return
       }
 
-      const snappedPoint = snapPolygonDraftPoint({
+      const angleSnap = activePolygonDraftPoints.length > 0 && !shiftPressed
+      const fallbackPoint = snapPolygonDraftPoint({
         point: planPoint,
         start: activePolygonDraftPoints[activePolygonDraftPoints.length - 1],
-        angleSnap: activePolygonDraftPoints.length > 0 && !shiftPressed,
+        angleSnap,
       })
 
       if (isCeilingBuildActive) {
-        emitFloorplanGridEvent('double-click', planPoint, event)
+        const snappedPoint = resolveCeilingPlanPointSnap({
+          rawPoint: planPoint,
+          fallbackPoint,
+          levelId,
+          altKey: event.altKey,
+          align: !angleSnap,
+        }).point
+        emitFloorplanGridEvent('double-click', snappedPoint, event)
         handleCeilingPlacementConfirm(snappedPoint)
         return
       }
 
       if (isZoneBuildActive) {
-        handleZonePlacementConfirm(snappedPoint)
+        handleZonePlacementConfirm(fallbackPoint)
       } else {
+        const snappedPoint = resolveSlabPlanPointSnap({
+          rawPoint: planPoint,
+          fallbackPoint,
+          levelId,
+          altKey: event.altKey,
+          align: !angleSnap,
+        }).point
         // Slab is registry-driven: forward the double-click so the 3D tool
         // commits the node (zone has no registry tool, so it commits locally).
-        emitFloorplanGridEvent('double-click', planPoint, event)
+        emitFloorplanGridEvent('double-click', snappedPoint, event)
         handleSlabPlacementConfirm(snappedPoint)
       }
     },
@@ -9146,6 +9184,7 @@ export function FloorplanPanel({
       isPolygonDraftBuildActive,
       isRoofBuildActive,
       isZoneBuildActive,
+      levelId,
       shiftPressed,
     ],
   )

packages/editor/src/components/editor/index.tsx

@@ -72,6 +72,7 @@ const PAINT_CURSOR_BADGE_COLOR = '#818cf8'
 const PAINT_CURSOR_BADGE_DISABLED_COLOR = '#94a3b8'
 const PAINT_CURSOR_BADGE_OFFSET_X = 14
 const PAINT_CURSOR_BADGE_OFFSET_Y = 14
+const SCENE_READY_FALLBACK_MS = 8000
 const EDITOR_HOVER_STYLES: HoverStyles = {
   default: { visibleColor: 0x00_aa_ff, hiddenColor: 0xf3_ff_47, strength: 5, pulse: true },
   delete: { visibleColor: 0xef_44_44, hiddenColor: 0x99_1b_1b, strength: 6, pulse: false },
@@ -895,6 +896,7 @@ const ViewerCanvas = memo(function ViewerCanvas({
         {/* 3D viewer — always mounted, hidden via CSS to avoid destroying the WebGL context */}
         <div
           className="relative min-w-0 flex-1 overflow-hidden"
+          data-pascal-viewer-3d
           ref={viewer3dRef}
           style={{ display: show3d ? undefined : 'none' }}
         >
@@ -1068,6 +1070,19 @@ export default function Editor({
     setIsViewerSceneReady(ready)
   }, [])
 
+  useEffect(() => {
+    if (isLoading || isSceneLoading || !hasLoadedInitialScene || isViewerSceneReady) return
+
+    const timer = window.setTimeout(() => {
+      console.warn('[editor] viewer scene readiness timed out; showing editor shell anyway', {
+        sceneReadyKey,
+      })
+      setIsViewerSceneReady(true)
+    }, SCENE_READY_FALLBACK_MS)
+
+    return () => window.clearTimeout(timer)
+  }, [hasLoadedInitialScene, isLoading, isSceneLoading, isViewerSceneReady, sceneReadyKey])
+
   const showLoader = isLoading || isSceneLoading || !hasLoadedInitialScene || !isViewerSceneReady
 
   const firstPersonPreviousLevelRef = useRef(useViewer.getState().selection.levelId)

packages/editor/src/components/editor/node-arrow-handles.tsx

@@ -38,11 +38,13 @@ import {
   Vector3,
 } from 'three'
 import { mergeGeometries } from 'three/examples/jsm/utils/BufferGeometryUtils.js'
+
 import { MeshBasicNodeMaterial } from 'three/webgpu'
 import { EDITOR_LAYER } from '../../lib/constants'
 import { createEditorApi } from '../../lib/editor-api'
 import { sfxEmitter } from '../../lib/sfx-bus'
 import useEditor from '../../store/use-editor'
+import { suppressBoxSelectForPointer } from '../tools/select/box-select-state'
 import { formatAngleRadians } from '../tools/shared/segment-angle'
 import {
   ARROW_COLOR,
@@ -54,6 +56,10 @@ import {
 } from './handles/handle-arrow'
 import { type HandleDragControls, useHandleDrag } from './handles/use-handle-drag'
 
+// Pooled scratch for the handle rig's world-relative pose mapping.
+const _rigRelative = new Matrix4()
+const _rigScratchScale = new Vector3()
+
 export {
   ARROW_COLOR,
   ARROW_HOVER_COLOR,
@@ -275,14 +281,32 @@ function NodeArrowHandlesForNode({
   // exclusion the wall arrow also goes without.
 
   useFrame(() => {
+    if (innerRef.current && innerRide && portalObject) {
+      // Grandparent mode: pose the rig by mapping the node's WORLD pose
+      // into the portal target's frame. Copying the parent + node
+      // registry poses (the previous approach) assumed the node mesh is
+      // a DIRECT child of the parent's registered object — roof-hosted
+      // openings break that with an intermediate face-frame group, which
+      // the world-relative mapping absorbs for free. For wall children
+      // the result is identical (portal⁻¹ ∘ node = wall.local ∘ node.local).
+      if (outerRef.current) {
+        outerRef.current.position.set(0, 0, 0)
+        outerRef.current.quaternion.identity()
+      }
+      portalObject.updateWorldMatrix(true, false)
+      innerRide.updateWorldMatrix(true, false)
+      _rigRelative.copy(portalObject.matrixWorld).invert().multiply(innerRide.matrixWorld)
+      _rigRelative.decompose(
+        innerRef.current.position,
+        innerRef.current.quaternion,
+        _rigScratchScale,
+      )
+      return
+    }
     if (outerRef.current && outerRide) {
       outerRef.current.position.copy(outerRide.position)
       outerRef.current.quaternion.copy(outerRide.quaternion)
     }
-    if (innerRef.current && innerRide) {
-      innerRef.current.position.copy(innerRide.position)
-      innerRef.current.quaternion.copy(innerRide.quaternion)
-    }
   })
 
   // Active-drag tracking. When a handle starts dragging, it claims its
@@ -1169,6 +1193,7 @@ function TranslateArrow({
   // 3D translate gizmo and the floating Move button behave identically.
   const activate = (event: ThreeEvent<PointerEvent>) => {
     event.stopPropagation()
+    suppressBoxSelectForPointer(event)
     sfxEmitter.emit('sfx:item-pick')
     useEditor.getState().setMovingNode(node as never)
     useViewer.getState().setSelection({ selectedIds: [] })

packages/editor/src/components/editor/use-floorplan-background-placement.ts

@@ -2,7 +2,9 @@
 
 import { emitter, type FenceNode, isCurvedWall, type WallNode } from '@pascal-app/core'
 import { type MouseEvent as ReactMouseEvent, useCallback } from 'react'
+import { resolveCeilingPlanPointSnap } from '../../lib/ceiling-plan-snap'
 import { alignFloorplanDraftPoint, getPlanPointDistance } from '../../lib/floorplan'
+import { resolveSlabPlanPointSnap } from '../../lib/slab-plan-snap'
 import { snapFenceDraftPoint } from '../tools/fence/fence-drafting'
 import {
   WALL_FINE_GRID_STEP,
@@ -49,8 +51,10 @@ type UseFloorplanBackgroundPlacementArgs = {
   isOpeningPlacementActive: boolean
   isPolygonBuildActive: boolean
   isRoofBuildActive: boolean
+  isSlabBuildActive: boolean
   isWallBuildActive: boolean
   isZoneBuildActive: boolean
+  levelId: string | null
   roofDraftStart: WallPlanPoint | null
   setCursorPoint: React.Dispatch<React.SetStateAction<WallPlanPoint | null>>
   setFenceDraftEnd: React.Dispatch<React.SetStateAction<WallPlanPoint | null>>
@@ -105,8 +109,10 @@ export function useFloorplanBackgroundPlacement({
   isOpeningPlacementActive,
   isPolygonBuildActive,
   isRoofBuildActive,
+  isSlabBuildActive,
   isWallBuildActive,
   isZoneBuildActive,
+  levelId,
   roofDraftStart,
   setCursorPoint,
   setFenceDraftEnd,
@@ -149,17 +155,22 @@ export function useFloorplanBackgroundPlacement({
 
       if (isCeilingBuildActive) {
         // Align the committed vertex the same way the move-preview did, so
-        // the placed point matches what the user saw. Skip when angle snap
-        // owns the vertex (matches the move branch).
+        // the placed point matches what the user saw. Wall magnetic snap may
+        // still win; generic alignment is skipped when angle snap owns the
+        // vertex (matches the move branch).
         const angleSnap = ceilingDraftPoints.length > 0 && !shiftPressed
-        let snappedPoint = snapPolygonDraftPoint({
+        const fallbackPoint = snapPolygonDraftPoint({
           point: planPoint,
           start: ceilingDraftPoints[ceilingDraftPoints.length - 1],
           angleSnap,
         })
-        if (!angleSnap) {
-          snappedPoint = alignFloorplanDraftPoint(snappedPoint, { bypass: event.altKey })
-        }
+        const snappedPoint = resolveCeilingPlanPointSnap({
+          rawPoint: planPoint,
+          fallbackPoint,
+          levelId,
+          altKey: event.altKey,
+          align: !angleSnap,
+        }).point
 
         emitFloorplanGridEvent('click', snappedPoint, event)
         handleCeilingPlacementPoint(snappedPoint)
@@ -225,13 +236,22 @@ export function useFloorplanBackgroundPlacement({
       // the 2D draft polygon invisible while the 3D tool builds fine).
       if (isPolygonBuildActive) {
         const angleSnap = activePolygonDraftPoints.length > 0 && !shiftPressed
-        let snappedPoint = snapPolygonDraftPoint({
+        const fallbackPoint = snapPolygonDraftPoint({
           point: planPoint,
           start: activePolygonDraftPoints[activePolygonDraftPoints.length - 1],
           angleSnap,
         })
-        if (!angleSnap) {
-          snappedPoint = alignFloorplanDraftPoint(snappedPoint, { bypass: event.altKey })
+        let snappedPoint = fallbackPoint
+        if (isSlabBuildActive) {
+          snappedPoint = resolveSlabPlanPointSnap({
+            rawPoint: planPoint,
+            fallbackPoint,
+            levelId,
+            altKey: event.altKey,
+            align: !angleSnap,
+          }).point
+        } else if (!angleSnap) {
+          snappedPoint = alignFloorplanDraftPoint(fallbackPoint, { bypass: event.altKey })
         }
 
         // Emit the grid event so the registry-driven slab tool also
@@ -320,8 +340,10 @@ export function useFloorplanBackgroundPlacement({
       isOpeningPlacementActive,
       isPolygonBuildActive,
       isRoofBuildActive,
+      isSlabBuildActive,
       isWallBuildActive,
       isZoneBuildActive,
+      levelId,
       roofDraftStart,
       setCursorPoint,
       setFenceDraftEnd,

packages/editor/src/components/editor/wall-snap-beacon-layer.tsx

@@ -1,10 +1,23 @@
 'use client'
 
-import { sceneRegistry } from '@pascal-app/core'
+import {
+  type AnyNode,
+  type AnyNodeId,
+  DEFAULT_WALL_HEIGHT,
+  getWallCurveFrameAt,
+  getWallCurveLength,
+  getWallThickness,
+  isCurvedWall,
+  resolveLevelId,
+  sceneRegistry,
+  spatialGridManager,
+  useScene,
+  type WallNode,
+} from '@pascal-app/core'
 import { useWallSnapIndicator, type WallSnapKind } from '@pascal-app/editor'
 import { useViewer } from '@pascal-app/viewer'
 import { useFrame } from '@react-three/fiber'
-import { memo, useRef } from 'react'
+import { memo, useMemo, useRef } from 'react'
 import { BoxGeometry, CircleGeometry, CylinderGeometry, type Group } from 'three'
 import { MeshBasicNodeMaterial } from 'three/webgpu'
 import { EDITOR_LAYER } from '../../lib/constants'
@@ -34,6 +47,14 @@ const BEACON_HEIGHT = 2.5 // world-meter height of the pillar
 const BEACON_RADIUS = 0.018 // world-meter radius of the pillar
 const MARKER = 0.13 // world-meter base size of the floor glyph
 const FLOOR_LIFT = 0.012 // tiny lift so the marker reads above the floor grid
+const WALL_TOP_HIGHLIGHT_LIFT = 0.035
+const WALL_TOP_HIGHLIGHT_HEIGHT = 0.018
+const WALL_TOP_HIGHLIGHT_OVERHANG = 0.14
+const WALL_TOP_GLOW_HEIGHT = 0.026
+const WALL_TOP_GLOW_OVERHANG = 0.36
+const WALL_TOP_END_OVERHANG = 0.08
+const CURVED_WALL_HIGHLIGHT_SEGMENT_LENGTH = 0.45
+const NO_RAYCAST = () => null
 
 // Shared resources — one material + unit geometries, so snap churn during a
 // drag doesn't rebuild GPU buffers (mirrors the alignment guide layer).
@@ -45,17 +66,41 @@ const beaconMaterial = new MeshBasicNodeMaterial({
   transparent: true,
   opacity: 0.9,
 })
+const wallTopHighlightMaterial = new MeshBasicNodeMaterial({
+  color: BEACON_COLOR,
+  depthTest: false,
+  depthWrite: false,
+  toneMapped: false,
+  transparent: true,
+  opacity: 0.88,
+})
+const wallTopHighlightGlowMaterial = new MeshBasicNodeMaterial({
+  color: BEACON_COLOR,
+  depthTest: false,
+  depthWrite: false,
+  toneMapped: false,
+  transparent: true,
+  opacity: 0.26,
+})
 const PILLAR_GEOMETRY = new CylinderGeometry(BEACON_RADIUS, BEACON_RADIUS, BEACON_HEIGHT, 8)
 // Flat unit geometries scaled per marker. Boxes are 0.002 tall so they read as
 // a flat plate; circles/triangles lie flat via an X rotation at the mesh.
 const FLAT_BOX_GEOMETRY = new BoxGeometry(1, 0.002, 1)
+const WALL_TOP_HIGHLIGHT_GEOMETRY = new BoxGeometry(1, 1, 1)
 const TRIANGLE_GEOMETRY = new CircleGeometry(1, 3)
 const CIRCLE_GEOMETRY = new CircleGeometry(1, 28)
 
 export const WallSnapBeaconLayer = memo(function WallSnapBeaconLayer() {
   const point = useWallSnapIndicator((s) => s.point)
   const levelId = useViewer((s) => s.selection.levelId)
+  const nodes = useScene((s) => s.nodes)
   const groupRef = useRef<Group>(null)
+  const highlightedWalls = useMemo(() => {
+    if (!point?.wallIds?.length) return []
+    return point.wallIds
+      .map((wallId) => nodes[wallId as AnyNodeId])
+      .filter((node): node is WallNode => node?.type === 'wall' && node.visible !== false)
+  }, [nodes, point?.wallIds])
 
   // Track the active level's building-local Y each frame so the beacon stands
   // on the floor being edited, not the building base — same source the
@@ -70,6 +115,9 @@ export const WallSnapBeaconLayer = memo(function WallSnapBeaconLayer() {
   if (!point) return null
   return (
     <group ref={groupRef}>
+      {highlightedWalls.map((wall) => (
+        <WallTopHighlight key={wall.id} nodes={nodes} wall={wall} />
+      ))}
       <mesh
         geometry={PILLAR_GEOMETRY}
         layers={EDITOR_LAYER}
@@ -82,6 +130,103 @@ export const WallSnapBeaconLayer = memo(function WallSnapBeaconLayer() {
   )
 })
 
+type WallTopHighlightSegment = {
+  angle: number
+  center: [number, number]
+  length: number
+}
+
+function getWallTopY(wall: WallNode, nodes: Readonly<Record<string, AnyNode>>) {
+  const levelId = resolveLevelId(wall, nodes as Record<string, AnyNode>)
+  const slabElevation = spatialGridManager.getSlabElevationForWall(
+    levelId,
+    wall.start,
+    wall.end,
+    wall.curveOffset ?? 0,
+    wall.thickness,
+  )
+  const wallHeight = wall.height ?? DEFAULT_WALL_HEIGHT
+  return (slabElevation > 0 ? slabElevation + wallHeight : wallHeight) + WALL_TOP_HIGHLIGHT_LIFT
+}
+
+function buildHighlightSegment(start: [number, number], end: [number, number]) {
+  const dx = end[0] - start[0]
+  const dz = end[1] - start[1]
+  const length = Math.hypot(dx, dz)
+  if (length < 1e-6) return null
+
+  return {
+    angle: -Math.atan2(dz, dx),
+    center: [(start[0] + end[0]) / 2, (start[1] + end[1]) / 2] as [number, number],
+    length,
+  }
+}
+
+function buildWallTopHighlightSegments(wall: WallNode): WallTopHighlightSegment[] {
+  if (!isCurvedWall(wall)) {
+    const segment = buildHighlightSegment(wall.start, wall.end)
+    return segment ? [segment] : []
+  }
+
+  const sampleCount = Math.max(
+    8,
+    Math.ceil(getWallCurveLength(wall) / CURVED_WALL_HIGHLIGHT_SEGMENT_LENGTH),
+  )
+  const segments: WallTopHighlightSegment[] = []
+  let previous = getWallCurveFrameAt(wall, 0).point
+  for (let index = 1; index <= sampleCount; index += 1) {
+    const current = getWallCurveFrameAt(wall, index / sampleCount).point
+    const segment = buildHighlightSegment([previous.x, previous.y], [current.x, current.y])
+    if (segment) segments.push(segment)
+    previous = current
+  }
+  return segments
+}
+
+function WallTopHighlight({
+  nodes,
+  wall,
+}: {
+  nodes: Readonly<Record<string, AnyNode>>
+  wall: WallNode
+}) {
+  const segments = useMemo(() => buildWallTopHighlightSegments(wall), [wall])
+  const y = getWallTopY(wall, nodes)
+  const width = Math.max(getWallThickness(wall) + WALL_TOP_HIGHLIGHT_OVERHANG, 0.24)
+  const glowWidth = Math.max(getWallThickness(wall) + WALL_TOP_GLOW_OVERHANG, 0.42)
+
+  return (
+    <>
+      {segments.map((segment, index) => (
+        <group key={`${wall.id}:${index}`}>
+          <mesh
+            frustumCulled={false}
+            geometry={WALL_TOP_HIGHLIGHT_GEOMETRY}
+            layers={EDITOR_LAYER}
+            material={wallTopHighlightGlowMaterial}
+            position={[segment.center[0], y - 0.003, segment.center[1]]}
+            raycast={NO_RAYCAST}
+            renderOrder={1003}
+            rotation={[0, segment.angle, 0]}
+            scale={[segment.length + WALL_TOP_END_OVERHANG, WALL_TOP_GLOW_HEIGHT, glowWidth]}
+          />
+          <mesh
+            frustumCulled={false}
+            geometry={WALL_TOP_HIGHLIGHT_GEOMETRY}
+            layers={EDITOR_LAYER}
+            material={wallTopHighlightMaterial}
+            position={[segment.center[0], y + 0.002, segment.center[1]]}
+            raycast={NO_RAYCAST}
+            renderOrder={1004}
+            rotation={[0, segment.angle, 0]}
+            scale={[segment.length + WALL_TOP_END_OVERHANG, WALL_TOP_HIGHLIGHT_HEIGHT, width]}
+          />
+        </group>
+      ))}
+    </>
+  )
+}
+
 /** Floor glyph whose shape encodes which kind of geometry the point snapped to. */
 function SnapMarker({ kind, x, z }: { kind: WallSnapKind; x: number; z: number }) {
   const y = FLOOR_LIFT

packages/editor/src/components/systems/ceiling/ceiling-selection-affordance-system.tsx

@@ -5,31 +5,90 @@ import {
   emitter,
   resolveLevelId,
   sceneRegistry,
+  useLiveNodeOverrides,
   useScene,
 } from '@pascal-app/core'
 import { useViewer } from '@pascal-app/viewer'
-import { createPortal, type ThreeEvent } from '@react-three/fiber'
-import { useEffect, useMemo, useState } from 'react'
-import type { Object3D } from 'three'
+import { createPortal, type ThreeEvent, useThree } from '@react-three/fiber'
+import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
+import { BoxGeometry, type Object3D, Plane, Raycaster, Vector2, Vector3 } from 'three'
 import { useShallow } from 'zustand/react/shallow'
+import {
+  clearCeilingSnapFeedback,
+  resolveCeilingPlanPointSnap,
+} from '../../../lib/ceiling-plan-snap'
+import { sfxEmitter } from '../../../lib/sfx-bus'
 import useEditor from '../../../store/use-editor'
+import { snapToHalf } from '../../tools/item/placement-math'
+import { suppressBoxSelectForPointer } from '../../tools/select/box-select-state'
 
 const BRACKET_THICKNESS = 0.04
 const BRACKET_HEIGHT = 0.04
 const BRACKET_Y_OFFSET = 0.035
 const HIT_BOX_SIZE: [number, number, number] = [0.28, 0.08, 0.28]
-// Draw the corner handles after everything else and with depth testing
-// off (see materials below) so they stay visible — and clickable — even
-// when a wall, roof, or the ceiling itself would otherwise occlude them.
+const HANDLE_COLOR = '#d4d4d4'
+const HANDLE_HOVER_COLOR = '#818cf8'
+const HANDLE_OPACITY = 0.72
+const HANDLE_HOVER_OPACITY = 0.92
+const HANDLE_DRAG_THRESHOLD_PX = 4
+const SHARED_HANDLE_BOX_GEOMETRY = new BoxGeometry(1, 1, 1)
+// Draw the corner handles after the ceiling surface so they read cleanly
+// when unobstructed, while material depth testing still lets other scene
+// geometry hide them.
 const CORNER_RENDER_ORDER = 1000
 
 type CornerBracketData = {
   corner: [number, number]
+  index: number
+  incomingEdgeIndex: number
   incomingDirection: [number, number]
+  outgoingEdgeIndex: number
   outgoingDirection: [number, number]
   incomingLength: number
   outgoingLength: number
-  cornerStrength: number
+}
+
+type CornerDragState = {
+  ceilingId: CeilingNode['id']
+  cornerIndex: number
+  didDrag: boolean
+  initialPolygon: Array<[number, number]>
+  inputDraggingSet: boolean
+  pointerId: number
+  previewPolygon: Array<[number, number]> | null
+  previousSnappedPosition: [number, number] | null
+  previousInputDragging: boolean
+  startClientX: number
+  startClientY: number
+  startPlanePosition: [number, number]
+}
+
+function stopHandlePointerDown(event: ThreeEvent<PointerEvent>) {
+  event.stopPropagation()
+  suppressBoxSelectForPointer(event, { markHandled: false })
+}
+
+function suppressNextClick() {
+  const suppressClick = (clickEvent: MouseEvent) => {
+    clickEvent.stopImmediatePropagation()
+    clickEvent.preventDefault()
+    window.removeEventListener('click', suppressClick, true)
+  }
+  window.addEventListener('click', suppressClick, true)
+  requestAnimationFrame(() => {
+    window.removeEventListener('click', suppressClick, true)
+  })
+}
+
+function clearCornerDragPreview(drag: CornerDragState) {
+  if (drag.didDrag) {
+    useLiveNodeOverrides.getState().clear(drag.ceilingId)
+    useScene.getState().markDirty(drag.ceilingId)
+  }
+  if (drag.inputDraggingSet) {
+    useViewer.getState().setInputDragging(drag.previousInputDragging)
+  }
+  clearCeilingSnapFeedback()
 }
 
 export const CeilingSelectionAffordanceSystem = () => {
@@ -79,11 +138,239 @@ const CeilingSelectionAffordance = ({
   ceiling: CeilingNode
   levelId: string
 }) => {
+  const { camera, gl } = useThree()
+  const liveOverride = useLiveNodeOverrides(
+    (state) => state.overrides.get(ceiling.id) as Partial<CeilingNode> | undefined,
+  )
+  const effectiveCeiling = useMemo(
+    () => (liveOverride ? ({ ...ceiling, ...liveOverride } as CeilingNode) : ceiling),
+    [ceiling, liveOverride],
+  )
   const [levelObject, setLevelObject] = useState<Object3D | null>(
     () => sceneRegistry.nodes.get(levelId) ?? null,
   )
+  const [hoveredCornerIndex, setHoveredCornerIndex] = useState<number | null>(null)
+  const [draggedCornerIndex, setDraggedCornerIndex] = useState<number | null>(null)
+  const [previewPolygon, setPreviewPolygon] = useState<Array<[number, number]> | null>(null)
+  const dragRef = useRef<CornerDragState | null>(null)
+  const raycasterRef = useRef(new Raycaster())
+  const ndcRef = useRef(new Vector2())
+  const planeRef = useRef(new Plane())
+  const planePointRef = useRef(new Vector3())
+  const planeNormalRef = useRef(new Vector3())
+  const planeOriginRef = useRef(new Vector3())
+  const intersectionRef = useRef(new Vector3())
+  const localIntersectionRef = useRef(new Vector3())
 
-  const corners = useMemo(() => buildCornerBrackets(ceiling.polygon), [ceiling.polygon])
+  const displayPolygon = previewPolygon ?? effectiveCeiling.polygon
+  const activeCornerIndex = draggedCornerIndex ?? hoveredCornerIndex
+  const corners = useMemo(() => buildCornerBrackets(displayPolygon), [displayPolygon])
+  const highlightedEdgeIndices = useMemo(() => {
+    const next = new Set<number>()
+    if (activeCornerIndex === null || displayPolygon.length < 2) return next
+    next.add(activeCornerIndex)
+    next.add((activeCornerIndex - 1 + displayPolygon.length) % displayPolygon.length)
+    return next
+  }, [activeCornerIndex, displayPolygon.length])
+  const highlightedCornerIndices = useMemo(() => {
+    const next = new Set<number>()
+    if (activeCornerIndex === null || displayPolygon.length < 2) return next
+    next.add(activeCornerIndex)
+    next.add((activeCornerIndex - 1 + displayPolygon.length) % displayPolygon.length)
+    next.add((activeCornerIndex + 1) % displayPolygon.length)
+    return next
+  }, [activeCornerIndex, displayPolygon.length])
+
+  useEffect(() => {
+    if (activeCornerIndex === null) return
+
+    useViewer.getState().setHoveredId(effectiveCeiling.id)
+    return () => {
+      if (useViewer.getState().hoveredId === effectiveCeiling.id) {
+        useViewer.getState().setHoveredId(null)
+      }
+    }
+  }, [activeCornerIndex, effectiveCeiling.id])
+
+  const selectCeilingForEdit = useCallback(() => {
+    const editor = useEditor.getState()
+    editor.setMovingNode(null)
+    editor.setMovingWallEndpoint(null)
+    editor.setCurvingWall(null)
+    editor.setEditingHole(null)
+    editor.setMode('select')
+    useViewer.getState().setSelection({ selectedIds: [effectiveCeiling.id] })
+  }, [effectiveCeiling.id])
+
+  const getHandlePlanePoint = useCallback(
+    (event: MouseEvent | PointerEvent): [number, number] | null => {
+      if (!levelObject) return null
+
+      const rect = gl.domElement.getBoundingClientRect()
+      ndcRef.current.set(
+        ((event.clientX - rect.left) / rect.width) * 2 - 1,
+        -((event.clientY - rect.top) / rect.height) * 2 + 1,
+      )
+      raycasterRef.current.setFromCamera(ndcRef.current, camera)
+
+      planePointRef.current.set(0, (effectiveCeiling.height ?? 2.5) + BRACKET_Y_OFFSET, 0)
+      levelObject.localToWorld(planePointRef.current)
+
+      planeOriginRef.current.set(0, 0, 0)
+      levelObject.localToWorld(planeOriginRef.current)
+      planeNormalRef.current.set(0, 1, 0)
+      levelObject.localToWorld(planeNormalRef.current)
+      planeNormalRef.current.sub(planeOriginRef.current).normalize()
+      planeRef.current.setFromNormalAndCoplanarPoint(planeNormalRef.current, planePointRef.current)
+
+      const hit = raycasterRef.current.ray.intersectPlane(planeRef.current, intersectionRef.current)
+      if (!hit) return null
+
+      localIntersectionRef.current.copy(intersectionRef.current)
+      levelObject.worldToLocal(localIntersectionRef.current)
+      return [localIntersectionRef.current.x, localIntersectionRef.current.z]
+    },
+    [camera, effectiveCeiling.height, gl.domElement, levelObject],
+  )
+
+  const handleCornerPointerDown = useCallback(
+    (corner: CornerBracketData, event: ThreeEvent<PointerEvent>) => {
+      if (event.button !== 0) return
+      stopHandlePointerDown(event)
+
+      const startPlanePosition = getHandlePlanePoint(event.nativeEvent)
+      if (!startPlanePosition) return
+      const initialCorner = effectiveCeiling.polygon[corner.index]
+      if (!initialCorner) return
+
+      dragRef.current = {
+        ceilingId: effectiveCeiling.id,
+        cornerIndex: corner.index,
+        didDrag: false,
+        initialPolygon: effectiveCeiling.polygon.map(([x, z]) => [x, z] as [number, number]),
+        inputDraggingSet: false,
+        pointerId: event.pointerId,
+        previewPolygon: null,
+        previousSnappedPosition: [initialCorner[0], initialCorner[1]],
+        previousInputDragging: useViewer.getState().inputDragging,
+        startClientX: event.nativeEvent.clientX,
+        startClientY: event.nativeEvent.clientY,
+        startPlanePosition,
+      }
+    },
+    [effectiveCeiling.id, effectiveCeiling.polygon, getHandlePlanePoint],
+  )
+
+  useEffect(() => {
+    const handlePointerMove = (event: PointerEvent) => {
+      const drag = dragRef.current
+      if (!drag || drag.ceilingId !== effectiveCeiling.id) return
+      if (event.pointerId !== drag.pointerId) return
+
+      const dragDistance = Math.hypot(
+        event.clientX - drag.startClientX,
+        event.clientY - drag.startClientY,
+      )
+
+      const planePosition = getHandlePlanePoint(event)
+      if (!planePosition) return
+
+      if (!drag.didDrag) {
+        if (dragDistance < HANDLE_DRAG_THRESHOLD_PX) return
+
+        drag.didDrag = true
+        drag.inputDraggingSet = true
+        useViewer.getState().setInputDragging(true)
+        setDraggedCornerIndex(drag.cornerIndex)
+        selectCeilingForEdit()
+        sfxEmitter.emit('sfx:item-pick')
+      }
+
+      const initialCorner = drag.initialPolygon[drag.cornerIndex]
+      if (!initialCorner) return
+
+      const rawNextPosition: [number, number] = [
+        initialCorner[0] + (planePosition[0] - drag.startPlanePosition[0]),
+        initialCorner[1] + (planePosition[1] - drag.startPlanePosition[1]),
+      ]
+      const gridNextPosition: [number, number] = [
+        initialCorner[0] + snapToHalf(planePosition[0] - drag.startPlanePosition[0]),
+        initialCorner[1] + snapToHalf(planePosition[1] - drag.startPlanePosition[1]),
+      ]
+      const nextPosition = resolveCeilingPlanPointSnap({
+        rawPoint: rawNextPosition,
+        fallbackPoint: gridNextPosition,
+        levelId,
+        excludeId: drag.ceilingId,
+        altKey: event.altKey,
+      }).point
+
+      if (
+        drag.previousSnappedPosition &&
+        (nextPosition[0] !== drag.previousSnappedPosition[0] ||
+          nextPosition[1] !== drag.previousSnappedPosition[1])
+      ) {
+        sfxEmitter.emit('sfx:grid-snap')
+      }
+      drag.previousSnappedPosition = nextPosition
+
+      const nextPolygon = drag.initialPolygon.map((polygonPoint, index) =>
+        index === drag.cornerIndex ? nextPosition : polygonPoint,
+      )
+
+      drag.previewPolygon = nextPolygon
+      setPreviewPolygon(nextPolygon)
+      useLiveNodeOverrides.getState().set(drag.ceilingId, { polygon: nextPolygon })
+      useScene.getState().markDirty(drag.ceilingId)
+    }
+
+    const finishDrag = (event: PointerEvent) => {
+      const drag = dragRef.current
+      if (!drag || event.pointerId !== drag.pointerId) return
+
+      dragRef.current = null
+      setDraggedCornerIndex(null)
+      setPreviewPolygon(null)
+
+      if (drag.didDrag) {
+        event.preventDefault()
+        suppressNextClick()
+
+        if (drag.previewPolygon) {
+          useScene.getState().updateNode(drag.ceilingId, { polygon: drag.previewPolygon })
+          useViewer.getState().setSelection({ selectedIds: [drag.ceilingId] })
+        }
+
+        sfxEmitter.emit('sfx:item-place')
+      }
+
+      clearCornerDragPreview(drag)
+    }
+
+    const cancelDrag = (event: PointerEvent) => {
+      const drag = dragRef.current
+      if (!drag || event.pointerId !== drag.pointerId) return
+
+      dragRef.current = null
+      setDraggedCornerIndex(null)
+      setPreviewPolygon(null)
+      clearCornerDragPreview(drag)
+    }
+
+    window.addEventListener('pointermove', handlePointerMove)
+    window.addEventListener('pointerup', finishDrag, true)
+    window.addEventListener('pointercancel', cancelDrag, true)
+    return () => {
+      window.removeEventListener('pointermove', handlePointerMove)
+      window.removeEventListener('pointerup', finishDrag, true)
+      window.removeEventListener('pointercancel', cancelDrag, true)
+
+      const drag = dragRef.current
+      if (!drag || drag.ceilingId !== effectiveCeiling.id) return
+      dragRef.current = null
+      clearCornerDragPreview(drag)
+    }
+  }, [effectiveCeiling.id, getHandlePlanePoint, levelId, selectCeilingForEdit])
 
   useEffect(() => {
     let frameId = 0
@@ -114,9 +401,28 @@ const CeilingSelectionAffordance = ({
   if (!levelObject || corners.length === 0) return null
 
   return createPortal(
-    <group position={[0, (ceiling.height ?? 2.5) + BRACKET_Y_OFFSET, 0]}>
+    <group position={[0, (effectiveCeiling.height ?? 2.5) + BRACKET_Y_OFFSET, 0]}>
       {corners.map((corner, index) => (
-        <CornerBracket ceiling={ceiling} corner={corner} key={`${ceiling.id}-corner-${index}`} />
+        <CornerBracket
+          ceiling={effectiveCeiling}
+          corner={corner}
+          highlightIncoming={highlightedEdgeIndices.has(corner.incomingEdgeIndex)}
+          highlightOutgoing={highlightedEdgeIndices.has(corner.outgoingEdgeIndex)}
+          isHovered={activeCornerIndex === corner.index}
+          isLinkedHovered={
+            activeCornerIndex !== null &&
+            activeCornerIndex !== corner.index &&
+            highlightedCornerIndices.has(corner.index)
+          }
+          key={`${ceiling.id}-corner-${index}`}
+          onHoverChange={(hovered) => {
+            setHoveredCornerIndex((current) => {
+              if (hovered) return corner.index
+              return current === corner.index ? null : current
+            })
+          }}
+          onPointerDown={(event) => handleCornerPointerDown(corner, event)}
+        />
       ))}
     </group>,
     levelObject,
@@ -126,21 +432,29 @@ const CeilingSelectionAffordance = ({
 const CornerBracket = ({
   ceiling,
   corner,
+  highlightIncoming,
+  highlightOutgoing,
+  isHovered,
+  isLinkedHovered,
+  onHoverChange,
+  onPointerDown,
 }: {
   ceiling: CeilingNode
   corner: CornerBracketData
+  highlightIncoming: boolean
+  highlightOutgoing: boolean
+  isHovered: boolean
+  isLinkedHovered: boolean
+  onHoverChange: (hovered: boolean) => void
+  onPointerDown: (event: ThreeEvent<PointerEvent>) => void
 }) => {
-  const [isHovered, setIsHovered] = useState(false)
-  const color = '#d4d4d4'
-  const opacity = 0.72
-  const cubeColor = isHovered ? '#818cf8' : '#d4d4d4'
-  const cubeOpacity = isHovered ? 0.92 : 0.72
+  const cubeHighlighted = isHovered || isLinkedHovered
+  const cubeColor = cubeHighlighted ? HANDLE_HOVER_COLOR : HANDLE_COLOR
+  const cubeOpacity = cubeHighlighted ? HANDLE_HOVER_OPACITY : HANDLE_OPACITY
 
   const handleClick = (e: ThreeEvent<MouseEvent>) => {
     e.stopPropagation()
 
-    const nodes = useScene.getState().nodes
-
     useEditor.getState().setMovingNode(null)
     useEditor.getState().setMovingWallEndpoint(null)
     useEditor.getState().setCurvingWall(null)
@@ -160,36 +474,42 @@ const CornerBracket = ({
   return (
     <group position={[corner.corner[0], 0, corner.corner[1]]}>
       <BracketLeg
-        color={color}
+        color={highlightIncoming ? HANDLE_HOVER_COLOR : HANDLE_COLOR}
         direction={corner.incomingDirection}
+        highlighted={highlightIncoming}
         length={corner.incomingLength}
         onClick={handleClick}
-        opacity={opacity}
+        onHoverChange={onHoverChange}
+        onPointerDown={onPointerDown}
       />
       <BracketLeg
-        color={color}
+        color={highlightOutgoing ? HANDLE_HOVER_COLOR : HANDLE_COLOR}
         direction={corner.outgoingDirection}
+        highlighted={highlightOutgoing}
         length={corner.outgoingLength}
         onClick={handleClick}
-        opacity={opacity}
+        onHoverChange={onHoverChange}
+        onPointerDown={onPointerDown}
       />
 
       <mesh
+        geometry={SHARED_HANDLE_BOX_GEOMETRY}
         onClick={handleClick}
+        onPointerDown={onPointerDown}
         onPointerEnter={(e) => {
           e.stopPropagation()
-          setIsHovered(true)
+          onHoverChange(true)
         }}
         onPointerLeave={(e) => {
           e.stopPropagation()
-          setIsHovered(false)
+          onHoverChange(false)
         }}
         renderOrder={CORNER_RENDER_ORDER}
+        scale={HIT_BOX_SIZE}
       >
-        <boxGeometry args={HIT_BOX_SIZE} />
         <meshBasicMaterial
           color={cubeColor}
-          depthTest={false}
+          depthTest
           depthWrite={false}
           opacity={cubeOpacity}
           transparent
@@ -203,16 +523,20 @@ const BracketLeg = ({
   direction,
   length,
   color,
+  highlighted,
   onClick,
-  opacity,
+  onHoverChange,
+  onPointerDown,
 }: {
   direction: [number, number]
   length: number
   color: string
+  highlighted: boolean
   onClick: (e: ThreeEvent<MouseEvent>) => void
-  opacity: number
+  onHoverChange: (hovered: boolean) => void
+  onPointerDown: (event: ThreeEvent<PointerEvent>) => void
 }) => {
-  const angle = Math.atan2(direction[1], direction[0])
+  const angle = -Math.atan2(direction[1], direction[0])
   const position: [number, number, number] = [
     direction[0] * (length / 2),
     0,
@@ -221,17 +545,27 @@ const BracketLeg = ({
 
   return (
     <mesh
+      geometry={SHARED_HANDLE_BOX_GEOMETRY}
       onClick={onClick}
+      onPointerDown={onPointerDown}
+      onPointerEnter={(e) => {
+        e.stopPropagation()
+        onHoverChange(true)
+      }}
+      onPointerLeave={(e) => {
+        e.stopPropagation()
+        onHoverChange(false)
+      }}
       position={position}
       renderOrder={CORNER_RENDER_ORDER}
       rotation={[0, angle, 0]}
+      scale={[length, BRACKET_HEIGHT, BRACKET_THICKNESS]}
     >
-      <boxGeometry args={[length, BRACKET_HEIGHT, BRACKET_THICKNESS]} />
       <meshBasicMaterial
         color={color}
-        depthTest={false}
+        depthTest
         depthWrite={false}
-        opacity={opacity}
+        opacity={highlighted ? HANDLE_HOVER_OPACITY : HANDLE_OPACITY}
         transparent
       />
     </mesh>
@@ -241,7 +575,7 @@ const BracketLeg = ({
 function buildCornerBrackets(polygon: Array<[number, number]>): CornerBracketData[] {
   if (polygon.length < 3) return []
 
-  const allCorners = polygon.map((corner, index) => {
+  return polygon.map((corner, index) => {
     const previous = polygon[(index - 1 + polygon.length) % polygon.length]!
     const next = polygon[(index + 1) % polygon.length]!
     const incomingVector = [previous[0] - corner[0], previous[1] - corner[1]] as [number, number]
@@ -251,35 +585,18 @@ function buildCornerBrackets(polygon: Array<[number, number]>): CornerBracketDat
 
     const incomingLength = Math.hypot(incomingVector[0], incomingVector[1])
     const outgoingLength = Math.hypot(outgoingVector[0], outgoingVector[1])
-    const cornerStrength =
-      1 -
-      Math.abs(
-        incomingDirection[0] * outgoingDirection[0] + incomingDirection[1] * outgoingDirection[1],
-      )
 
     return {
       corner,
+      index,
+      incomingEdgeIndex: (index - 1 + polygon.length) % polygon.length,
       incomingDirection,
+      outgoingEdgeIndex: index,
       outgoingDirection,
       incomingLength: getBracketLength(incomingLength),
       outgoingLength: getBracketLength(outgoingLength),
-      cornerStrength,
     }
   })
-
-  if (allCorners.length <= 4) {
-    return allCorners
-  }
-
-  const selectedIndices = new Set(
-    allCorners
-      .map((corner, index) => ({ index, strength: corner.cornerStrength }))
-      .sort((a, b) => b.strength - a.strength)
-      .slice(0, 4)
-      .map(({ index }) => index),
-  )
-
-  return allCorners.filter((_, index) => selectedIndices.has(index))
 }
 
 function normalize2D(vector: [number, number]): [number, number] {

packages/editor/src/components/systems/ceiling/ceiling-system.tsx

@@ -1,17 +1,89 @@
 import { type AnyNodeId, sceneRegistry, useScene } from '@pascal-app/core'
 import { useViewer } from '@pascal-app/viewer'
 import { useEffect } from 'react'
+import { Color, type Material, type Mesh } from 'three'
 import useEditor from '../../../store/use-editor'
 
+const CEILING_GRID_HIGHLIGHT_COLOR = '#ffffff'
+const CEILING_GRID_BASE_MATERIAL_KEY = '__pascalCeilingGridBaseMaterial'
+const CEILING_GRID_HIGHLIGHT_MATERIAL_KEY = '__pascalCeilingGridHighlightMaterial'
+
+type CeilingGridUserData = {
+  [CEILING_GRID_BASE_MATERIAL_KEY]?: Material | Material[]
+  [CEILING_GRID_HIGHLIGHT_MATERIAL_KEY]?: Material | Material[]
+}
+
+type HighlightableMaterial = Material & {
+  color?: Color
+  depthWrite?: boolean
+  needsUpdate?: boolean
+  opacity?: number
+  transparent?: boolean
+}
+
+function cloneCeilingGridHighlightMaterial(material: Material | Material[]): Material | Material[] {
+  const cloneOne = (entry: Material): Material => {
+    const clone = entry.clone() as HighlightableMaterial
+    if (clone.color instanceof Color) {
+      clone.color.set(CEILING_GRID_HIGHLIGHT_COLOR)
+    }
+    clone.depthWrite = false
+    clone.opacity = 1
+    clone.transparent = true
+    clone.needsUpdate = true
+    return clone
+  }
+
+  return Array.isArray(material) ? material.map(cloneOne) : cloneOne(material)
+}
+
+function disposeMaterial(material: Material | Material[] | undefined) {
+  if (!material) return
+  const materials = Array.isArray(material) ? material : [material]
+  for (const entry of materials) {
+    entry.dispose()
+  }
+}
+
+function setCeilingGridHighlighted(ceilingGrid: Mesh, highlighted: boolean) {
+  const userData = ceilingGrid.userData as CeilingGridUserData
+
+  if (highlighted) {
+    if (!userData[CEILING_GRID_BASE_MATERIAL_KEY]) {
+      userData[CEILING_GRID_BASE_MATERIAL_KEY] = ceilingGrid.material
+      userData[CEILING_GRID_HIGHLIGHT_MATERIAL_KEY] = cloneCeilingGridHighlightMaterial(
+        ceilingGrid.material,
+      )
+    }
+
+    const highlightMaterial = userData[CEILING_GRID_HIGHLIGHT_MATERIAL_KEY]
+    if (highlightMaterial) {
+      ceilingGrid.material = highlightMaterial
+    }
+    return
+  }
+
+  const baseMaterial = userData[CEILING_GRID_BASE_MATERIAL_KEY]
+  if (baseMaterial) {
+    ceilingGrid.material = baseMaterial
+  }
+  disposeMaterial(userData[CEILING_GRID_HIGHLIGHT_MATERIAL_KEY])
+  delete userData[CEILING_GRID_BASE_MATERIAL_KEY]
+  delete userData[CEILING_GRID_HIGHLIGHT_MATERIAL_KEY]
+}
+
 export const CeilingSystem = () => {
   const tool = useEditor((state) => state.tool)
   const selectedItem = useEditor((state) => state.selectedItem)
   const movingNode = useEditor((state) => state.movingNode)
   const selectedIds = useViewer((state) => state.selection.selectedIds)
   const activeLevelId = useViewer((state) => state.selection.levelId)
+  const hoveredId = useViewer((state) => state.hoveredId)
 
   useEffect(() => {
     const nodes = useScene.getState().nodes
+    const hoveredNode = hoveredId ? nodes[hoveredId as AnyNodeId] : null
+    const hoveredCeilingId = hoveredNode?.type === 'ceiling' ? hoveredNode.id : null
 
     const levelsToShowCeilings = new Set<string>()
 
@@ -54,7 +126,7 @@ export const CeilingSystem = () => {
     ceilings.forEach((ceiling) => {
       const mesh = sceneRegistry.nodes.get(ceiling)
       if (mesh) {
-        const ceilingGrid = mesh.getObjectByName('ceiling-grid')
+        const ceilingGrid = mesh.getObjectByName('ceiling-grid') as Mesh | undefined
         if (ceilingGrid) {
           let belongsToVisibleLevel = false
           let currentId: string | null = ceiling
@@ -68,14 +140,18 @@ export const CeilingSystem = () => {
             currentId = node?.parentId as string | null
           }
 
+          const shouldHighlightGrid = ceiling === hoveredCeilingId
           const shouldShowGrid =
-            belongsToVisibleLevel || (levelsToShowCeilings.size === 0 && isCeilingToolActive)
+            shouldHighlightGrid ||
+            belongsToVisibleLevel ||
+            (levelsToShowCeilings.size === 0 && isCeilingToolActive)
 
+          setCeilingGridHighlighted(ceilingGrid, shouldHighlightGrid)
           ceilingGrid.visible = shouldShowGrid
           ceilingGrid.scale.setScalar(shouldShowGrid ? 1 : 0.0) // Scale down to zero to prevent event interference when grid is hidden
         }
       }
     })
-  }, [tool, selectedItem, movingNode, selectedIds, activeLevelId])
+  }, [tool, selectedItem, movingNode, selectedIds, activeLevelId, hoveredId])
   return null
 }

packages/editor/src/components/systems/roof/roof-edit-system.tsx

@@ -18,6 +18,8 @@ function makeEmptySegmentGeometry(): THREE.BufferGeometry {
   // meshes are drawn. An empty position (count 0) leaves WebGPU vertex buffer
   // slot 0 unbound and the draw is rejected, poisoning the command encoder.
   g.setAttribute('position', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
+  g.setAttribute('normal', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
+  g.setAttribute('uv', new THREE.Float32BufferAttribute(new Float32Array(6), 2))
   // Match the four material slots the roof-segment renderer's material
   // array expects (0=top, 1=side, 2=interior, 3=shingle). Without these
   // groups, mesh.material is a single-material lookup that mismatches

packages/editor/src/components/tools/item/placement-strategies.ts

@@ -6,19 +6,27 @@ import type {
   GridEvent,
   ItemEvent,
   ItemNode,
+  RoofEvent,
+  RoofNode,
+  RoofSegmentNode,
+  RoofWallFaceId,
   ShelfEvent,
   ShelfNode,
   WallEvent,
   WallNode,
 } from '@pascal-app/core'
 import {
+  clampRectToRoofWallFace,
+  getRoofSegmentWallFace,
   getScaledDimensions,
   isLowProfileItemSurface,
   nodeRegistry,
+  roofFacePointToSegment,
   sceneRegistry,
   useScene,
 } from '@pascal-app/core'
 import { Euler, Matrix3, Quaternion, Vector3 } from 'three'
+import { hasRoofFaceChildOverlap, resolveRoofWallHit } from '../../../lib/roof-wall-hit'
 import { snapWorldXZForActiveBuilding } from '../../../lib/world-grid-snap'
 import {
   calculateCursorRotation,
@@ -211,10 +219,13 @@ export const wallStrategy = {
     const adjustedY = validation.adjustedY ?? y
 
     return {
-      stateUpdate: { surface: 'wall', wallId: event.node.id },
+      stateUpdate: { surface: 'wall', wallId: event.node.id, roofSegmentId: null },
       nodeUpdate: {
         position: [x, adjustedY, z],
         parentId: event.node.id,
+        // The draft may arrive from a roof-segment wall face.
+        roofSegmentId: undefined,
+        roofFace: undefined,
         side,
         rotation: [0, itemRotation, 0],
       },
@@ -313,6 +324,8 @@ export const wallStrategy = {
       nodeUpdate: {
         position: [ctx.gridPosition.x, ctx.gridPosition.y, ctx.gridPosition.z],
         parentId: event.node.id,
+        roofSegmentId: undefined,
+        roofFace: undefined,
         side: ctx.draftItem.side,
         rotation: ctx.draftItem.rotation,
         metadata: stripTransient(ctx.draftItem.metadata),
@@ -342,6 +355,223 @@ export const wallStrategy = {
   },
 }
 
+// ============================================================================
+// ROOF WALL STRATEGY
+// ============================================================================
+
+type RoofWallTarget = {
+  segment: RoofSegmentNode
+  faceId: RoofWallFaceId
+  faceYaw: number
+  /** Stored node position: FACE-LOCAL, y = bottom edge. */
+  position: [number, number, number]
+  /** Face-coord center of the placed rect (for the overlap guard). */
+  centerU: number
+  centerV: number
+  width: number
+  height: number
+  cursorPosition: [number, number, number]
+  cursorRotationY: number
+}
+
+/**
+ * Resolve a roof pointer event to an item placement on a segment wall
+ * face. Items snap u / bottom-v to the 0.5m grid, then the rect is
+ * clamped inside the face profile (sliding under the gable slopes).
+ * Position frame matches wall hosting: y anchors the BOTTOM edge;
+ * `wall-side` items mount on the outer surface, `wall` items center in
+ * the wall thickness.
+ *
+ * `shiftFree` mirrors the wall flow's Shift override (stubbed
+ * validators): the profile clamp is skipped, so the rect may overhang
+ * the face edges — placement follows the snapped cursor as-is.
+ */
+function resolveRoofWallTarget(
+  ctx: PlacementContext,
+  event: RoofEvent,
+  shiftFree = false,
+): RoofWallTarget | null {
+  const attachTo = ctx.asset.attachTo
+  if (attachTo !== 'wall' && attachTo !== 'wall-side') return null
+
+  const hit = resolveRoofWallHit(event.node as RoofNode, event.position, event.normal, event.object)
+  if (!hit) return null
+
+  const rawDims = ctx.draftItem
+    ? getScaledDimensions(ctx.draftItem)
+    : (ctx.asset.dimensions ?? DEFAULT_DIMENSIONS)
+  const dims = getGridAlignedDimensions(rawDims, attachTo)
+  const [width, height] = dims
+
+  const u = snapToHalf(hit.u)
+  const centerV = snapToHalf(hit.v) + height / 2
+  const fitted = shiftFree ? null : clampRectToRoofWallFace(hit.face, u, centerV, width, height)
+  if (!fitted && !shiftFree) return null
+  const finalU = fitted?.u ?? u
+  const finalV = fitted?.v ?? centerV
+
+  // FACE-LOCAL storage (z = 0 → wall mid-plane; ItemSystem pushes
+  // wall-side items to the outer surface, exactly like wall hosting).
+  // The renderer mounts the node inside the live face frame, so items
+  // track segment resizes without any re-anchoring.
+  const position: [number, number, number] = [finalU, finalV - height / 2, 0]
+
+  const segObj = sceneRegistry.nodes.get(hit.segment.id)
+  if (!segObj) return null
+  segObj.updateWorldMatrix(true, false)
+  const segLocal = roofFacePointToSegment(hit.segment, hit.face.id, position)
+  const worldPos = segObj.localToWorld(new Vector3(segLocal[0], segLocal[1], segLocal[2]))
+
+  const nodes = useScene.getState().nodes
+  const roof = hit.segment.parentId
+    ? (nodes[hit.segment.parentId as AnyNodeId] as RoofNode | undefined)
+    : undefined
+
+  return {
+    segment: hit.segment,
+    faceId: hit.face.id,
+    faceYaw: hit.face.yaw,
+    position,
+    centerU: finalU,
+    centerV: finalV,
+    width,
+    height,
+    cursorPosition: [worldPos.x, worldPos.y, worldPos.z],
+    cursorRotationY: (roof?.rotation ?? 0) + (hit.segment.rotation ?? 0) + hit.face.yaw,
+  }
+}
+
+/** Validation half of `checkCanPlace` for the roof-wall surface. */
+function canPlaceOnRoofWall(ctx: PlacementContext): boolean {
+  const segmentId = ctx.state.roofSegmentId
+  if (!(segmentId && ctx.draftItem)) return false
+  const segment = useScene.getState().nodes[segmentId as AnyNodeId] as RoofSegmentNode | undefined
+  if (segment?.type !== 'roof-segment') return false
+  const faceId = ctx.draftItem.roofFace
+  if (!faceId) return false
+  const face = getRoofSegmentWallFace(segment, faceId)
+
+  const dims = getGridAlignedDimensions(
+    getScaledDimensions(ctx.draftItem),
+    ctx.draftItem.asset.attachTo,
+  )
+  const [width, height] = dims
+  // gridPosition carries the stored FACE-LOCAL coords (u, bottom-v, z).
+  const u = ctx.gridPosition.x
+  const centerV = ctx.gridPosition.y + height / 2
+  const clamped = clampRectToRoofWallFace(face, u, centerV, width, height)
+  if (!clamped || Math.abs(clamped.u - u) > 1e-3 || Math.abs(clamped.v - centerV) > 1e-3) {
+    return false
+  }
+  return !hasRoofFaceChildOverlap(segment, faceId, u, centerV, width, height, ctx.draftItem.id)
+}
+
+export const roofWallStrategy = {
+  /**
+   * Handle roof:enter / first hover — transition onto a segment wall
+   * face. Returns null when the item doesn't wall-attach or the pointer
+   * isn't over a placeable face.
+   */
+  enter(ctx: PlacementContext, event: RoofEvent, shiftFree = false): TransitionResult | null {
+    const target = resolveRoofWallTarget(ctx, event, shiftFree)
+    if (!target) return null
+
+    return {
+      stateUpdate: { surface: 'roof-wall', roofSegmentId: target.segment.id, wallId: null },
+      nodeUpdate: {
+        position: target.position,
+        parentId: target.segment.id,
+        roofSegmentId: target.segment.id,
+        roofFace: target.faceId,
+        wallId: undefined,
+        side: 'front',
+        rotation: [0, 0, 0],
+      },
+      cursorRotationY: target.cursorRotationY,
+      gridPosition: target.position,
+      cursorPosition: target.cursorPosition,
+      stopPropagation: true,
+    }
+  },
+
+  /**
+   * Handle roof:move while on a segment wall face. Returns null when the
+   * pointer resolves to a DIFFERENT segment (the coordinator re-enters —
+   * segment transitions inside one roof never re-fire roof:enter) or to
+   * no placeable face.
+   */
+  move(ctx: PlacementContext, event: RoofEvent, shiftFree = false): PlacementResult | null {
+    if (ctx.state.surface !== 'roof-wall') return null
+    if (!ctx.draftItem) return null
+
+    const target = resolveRoofWallTarget(ctx, event, shiftFree)
+    if (!target) return null
+    if (target.segment.id !== ctx.state.roofSegmentId) return null
+
+    return {
+      gridPosition: target.position,
+      cursorPosition: target.cursorPosition,
+      cursorRotationY: target.cursorRotationY,
+      nodeUpdate: {
+        position: target.position,
+        side: 'front',
+        rotation: [0, 0, 0],
+        roofFace: target.faceId,
+      },
+      stopPropagation: true,
+      // Items don't cut the roof — no geometry rebuild needed.
+      dirtyNodeId: null,
+    }
+  },
+
+  /**
+   * Handle roof:click — commit placement on the segment wall face.
+   */
+  click(ctx: PlacementContext, _event: RoofEvent, shiftFree = false): CommitResult | null {
+    if (ctx.state.surface !== 'roof-wall') return null
+    if (!(ctx.draftItem && ctx.state.roofSegmentId)) return null
+    // Shift mirrors the wall flow's stubbed validators: skip profile-fit
+    // and overlap checks entirely.
+    if (!shiftFree && !canPlaceOnRoofWall(ctx)) return null
+
+    return {
+      nodeUpdate: {
+        position: [ctx.gridPosition.x, ctx.gridPosition.y, ctx.gridPosition.z],
+        parentId: ctx.state.roofSegmentId,
+        roofSegmentId: ctx.state.roofSegmentId,
+        roofFace: ctx.draftItem.roofFace,
+        wallId: undefined,
+        side: 'front',
+        rotation: [0, 0, 0],
+        metadata: stripTransient(ctx.draftItem.metadata),
+      },
+      stopPropagation: true,
+      dirtyNodeId: null,
+    }
+  },
+
+  /**
+   * Handle roof:leave — transition back to floor surface.
+   */
+  leave(ctx: PlacementContext): TransitionResult | null {
+    if (ctx.state.surface !== 'roof-wall') return null
+
+    return {
+      stateUpdate: { surface: 'floor', roofSegmentId: null },
+      nodeUpdate: {
+        position: [ctx.gridPosition.x, ctx.gridPosition.y, ctx.gridPosition.z],
+        parentId: ctx.levelId,
+        roofSegmentId: undefined,
+        roofFace: undefined,
+      },
+      cursorRotationY: 0,
+      gridPosition: [ctx.gridPosition.x, ctx.gridPosition.y, ctx.gridPosition.z],
+      cursorPosition: [ctx.gridPosition.x, ctx.gridPosition.y, ctx.gridPosition.z],
+      stopPropagation: true,
+    }
+  },
+}
+
 // ============================================================================
 // CEILING STRATEGY
 // ============================================================================
@@ -794,6 +1024,9 @@ export function checkCanPlace(ctx: PlacementContext, validators: SpatialValidato
   }
 
   if (attachTo === 'wall' || attachTo === 'wall-side') {
+    if (ctx.state.surface === 'roof-wall') {
+      return canPlaceOnRoofWall(ctx)
+    }
     if (ctx.state.surface !== 'wall' || !ctx.state.wallId) return false
     return validators.canPlaceOnWall(
       ctx.levelId,

packages/editor/src/components/tools/item/placement-types.ts

@@ -12,7 +12,13 @@ import type { Vector3 } from 'three'
 // PLACEMENT STATE
 // ============================================================================
 
-export type SurfaceType = 'floor' | 'wall' | 'ceiling' | 'item-surface' | 'shelf-surface'
+export type SurfaceType =
+  | 'floor'
+  | 'wall'
+  | 'roof-wall'
+  | 'ceiling'
+  | 'item-surface'
+  | 'shelf-surface'
 
 /**
  * Tracks which surface the draft item is currently on.
@@ -21,6 +27,12 @@ export type SurfaceType = 'floor' | 'wall' | 'ceiling' | 'item-surface' | 'shelf
 export interface PlacementState {
   surface: SurfaceType
   wallId: string | null
+  /**
+   * Active roof-segment when `surface === 'roof-wall'` — wall-attach
+   * items also host on the vertical wall faces a roof segment generates
+   * (base walls + coplanar gable ends).
+   */
+  roofSegmentId: string | null
   ceilingId: string | null
   surfaceItemId: string | null
   /**

packages/editor/src/components/tools/item/use-draft-node.ts

@@ -15,6 +15,10 @@ interface OriginalState {
   rotation: [number, number, number]
   side: ItemNode['side']
   parentId: string | null
+  // Roof-segment wall hosting — cleared/changed by surface transitions
+  // mid-move, so reverts must restore it alongside parentId.
+  roofSegmentId: ItemNode['roofSegmentId']
+  roofFace: ItemNode['roofFace']
   metadata: ItemNode['metadata']
 }
 
@@ -92,6 +96,8 @@ export function useDraftNode(): DraftNodeHandle {
       rotation: [...node.rotation] as [number, number, number],
       side: node.side,
       parentId: node.parentId,
+      roofSegmentId: node.roofSegmentId,
+      roofFace: node.roofFace,
       metadata: node.metadata,
     }
 
@@ -121,6 +127,8 @@ export function useDraftNode(): DraftNodeHandle {
         rotation: original.rotation,
         side: original.side,
         parentId: original.parentId,
+        roofSegmentId: original.roofSegmentId,
+        roofFace: original.roofFace,
         metadata: original.metadata,
       })
 
@@ -133,6 +141,15 @@ export function useDraftNode(): DraftNodeHandle {
         side: updateProps.side ?? draft.side,
         metadata: updateProps.metadata ?? stripTransient(draft.metadata),
         parentId: parentId as string,
+        // Forward the roof host explicitly: strategies set it on every
+        // commit (segment id on a roof face, undefined elsewhere), and
+        // dropping it here strands the item in the roof frame without
+        // the segment transform.
+        roofSegmentId: updateProps.roofSegmentId,
+        roofFace: updateProps.roofFace,
+        // Only when the strategy decided about wallId (roof commits clear
+        // it) — floor/ceiling commits never managed the field.
+        ...('wallId' in updateProps ? { wallId: updateProps.wallId } : {}),
       })
 
       useScene.temporal.getState().pause()
@@ -163,6 +180,11 @@ export function useDraftNode(): DraftNodeHandle {
       rotation: updateProps.rotation ?? draft.rotation,
       scale: updateProps.scale ?? draft.scale,
       side: updateProps.side ?? draft.side,
+      // Roof host — see the move-mode commit above for why this must be
+      // forwarded explicitly.
+      roofSegmentId: updateProps.roofSegmentId,
+      roofFace: updateProps.roofFace,
+      ...('wallId' in updateProps ? { wallId: updateProps.wallId } : {}),
       metadata: updateProps.metadata ?? stripTransient(draft.metadata),
     })
     useScene.getState().createNode(finalNode, parentId)
@@ -207,6 +229,8 @@ export function useDraftNode(): DraftNodeHandle {
         rotation: original.rotation,
         side: original.side,
         parentId: original.parentId,
+        roofSegmentId: original.roofSegmentId,
+        roofFace: original.roofFace,
         metadata: original.metadata,
       })
 

packages/editor/src/components/tools/item/use-placement-coordinator.tsx

@@ -10,6 +10,7 @@ import {
   getScaledDimensions,
   type ItemEvent,
   movingFootprintAnchors,
+  type RoofEvent,
   resolveLevelId,
   type ShelfEvent,
   sceneRegistry,
@@ -57,6 +58,7 @@ import {
   checkCanPlace,
   floorStrategy,
   itemSurfaceStrategy,
+  roofWallStrategy,
   shelfSurfaceStrategy,
   wallStrategy,
 } from './placement-strategies'
@@ -203,6 +205,7 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
     config.initialState ?? {
       surface: 'floor',
       wallId: null,
+      roofSegmentId: null,
       ceilingId: null,
       surfaceItemId: null,
       shelfId: null,
@@ -403,6 +406,7 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
     placementState.current = configRef.current.initialState ?? {
       surface: 'floor',
       wallId: null,
+      roofSegmentId: null,
       ceilingId: null,
       surfaceItemId: null,
       shelfId: null,
@@ -977,6 +981,145 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
       }
     }
 
+    // ---- Roof Wall Handlers ----
+    // Wall-attach items also host on the vertical wall faces a roof
+    // segment generates (base walls + coplanar gable ends). Unlike walls,
+    // crossing between segments inside ONE roof never re-fires
+    // `roof:enter` (events come from the roof group), so the move handler
+    // re-enters whenever the strategy reports a segment change.
+
+    const enterRoofWall = (event: RoofEvent): boolean => {
+      const result = roofWallStrategy.enter(getContext(), event, shiftFreeRef.current)
+      if (!result) return false
+
+      event.stopPropagation()
+      applyTransition(result)
+
+      if (!draftNode.current) {
+        ensureDraft(result)
+      } else if (result.nodeUpdate.parentId) {
+        // Existing draft (move mode): reparent to the segment
+        useScene.getState().updateNode(draftNode.current.id, result.nodeUpdate)
+      }
+      return true
+    }
+
+    const onRoofWallEnter = (event: RoofEvent) => {
+      has3DPointerDrivenMoveRef.current = true
+      enterRoofWall(event)
+    }
+
+    const onRoofWallMove = (event: RoofEvent) => {
+      releaseCommit = () => onRoofWallClick(event)
+      has3DPointerDrivenMoveRef.current = true
+      if (!cursorGroupRef.current) return
+      const ctx = getContext()
+
+      if (ctx.state.surface !== 'roof-wall' || !draftNode.current) {
+        enterRoofWall(event)
+        return
+      }
+
+      const result = roofWallStrategy.move(ctx, event, shiftFreeRef.current)
+      if (!result) {
+        // Different segment under the pointer (or no placeable face) —
+        // try a fresh enter; a null resolve leaves the draft where it is.
+        enterRoofWall(event)
+        return
+      }
+
+      event.stopPropagation()
+
+      const posChanged =
+        gridPosition.current.x !== result.gridPosition[0] ||
+        gridPosition.current.y !== result.gridPosition[1] ||
+        gridPosition.current.z !== result.gridPosition[2]
+
+      if (posChanged) {
+        sfxEmitter.emit('sfx:grid-snap')
+      }
+
+      gridPosition.current.set(...result.gridPosition)
+      const wc = worldToBuildingLocal(...result.cursorPosition)
+      cursorGroupRef.current.position.set(wc.x, wc.y, wc.z)
+      cursorGroupRef.current.rotation.y = result.cursorRotationY
+
+      const draft = draftNode.current
+      if (draft && result.nodeUpdate) {
+        if ('side' in result.nodeUpdate) draft.side = result.nodeUpdate.side
+        if ('rotation' in result.nodeUpdate)
+          draft.rotation = result.nodeUpdate.rotation as [number, number, number]
+      }
+
+      const placeable = revalidate()
+
+      if (draft && placeable) {
+        draft.position = result.gridPosition
+        const mesh = sceneRegistry.nodes.get(draft.id)
+        if (mesh) {
+          mesh.position.copy(gridPosition.current)
+          // Wall-side items sit on the outer surface: mirror ItemSystem's
+          // push (z = thickness/2 off the face frame's mid-plane) so the
+          // drag preview doesn't sink into the wall until commit.
+          if (asset.attachTo === 'wall-side' && placementState.current.roofSegmentId) {
+            const segment =
+              useScene.getState().nodes[placementState.current.roofSegmentId as AnyNodeId]
+            if (segment?.type === 'roof-segment') {
+              mesh.position.z = (segment.wallThickness ?? 0.1) / 2
+            }
+          }
+          const rot = result.nodeUpdate?.rotation
+          if (rot) mesh.rotation.y = rot[1]
+        }
+        // The 2D floor-plan live frame is wall-local; a segment-local
+        // value would render garbage — clear instead of publishing.
+        useLiveTransforms.getState().clear(draft.id)
+      }
+    }
+
+    const onRoofWallClick = (event: RoofEvent) => {
+      const result = roofWallStrategy.click(getContext(), event, shiftFreeRef.current)
+      if (!result) return
+
+      event.stopPropagation()
+      if (draftNode.current) {
+        useLiveTransforms.getState().clear(draftNode.current.id)
+      }
+      draftNode.commit(result.nodeUpdate)
+
+      if (configRef.current.onCommitted()) {
+        const enterResult = roofWallStrategy.enter(getContext(), event, shiftFreeRef.current)
+        if (enterResult) {
+          applyTransition(enterResult)
+        } else {
+          revalidate()
+        }
+      }
+    }
+
+    const onRoofWallLeave = (event: RoofEvent) => {
+      const result = roofWallStrategy.leave(getContext())
+      if (!result) return
+
+      event.stopPropagation()
+
+      if (draftNode.isAdopted) {
+        // Move mode: keep draft alive, reparent to level
+        applyTransition(result)
+        const draft = draftNode.current
+        if (draft) {
+          useScene.getState().updateNode(draft.id, {
+            parentId: result.nodeUpdate.parentId as string,
+            roofSegmentId: undefined,
+          })
+        }
+      } else {
+        // Create mode: destroy transient and reset state
+        draftNode.destroy()
+        Object.assign(placementState.current, result.stateUpdate)
+      }
+    }
+
     // ---- Item Surface Handlers ----
 
     const detachItemSurfaceToFloor = (event: ItemEvent) => {
@@ -1489,6 +1632,10 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
       const draft = draftNode.current
       if (!draft) return
 
+      // Roof-wall drafts live flat in the host face frame (yaw 0) —
+      // manual rotation would skew them off the wall plane.
+      if (placementState.current.surface === 'roof-wall') return
+
       let rotationDelta = 0
       if ((event.key === 'r' || event.key === 'R') && !event.metaKey && !event.ctrlKey)
         rotationDelta = ROTATION_STEP
@@ -1663,6 +1810,10 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
     emitter.on('wall:move', onWallMove)
     emitter.on('wall:click', onWallClick)
     emitter.on('wall:leave', onWallLeave)
+    emitter.on('roof:enter', onRoofWallEnter)
+    emitter.on('roof:move', onRoofWallMove)
+    emitter.on('roof:click', onRoofWallClick)
+    emitter.on('roof:leave', onRoofWallLeave)
     emitter.on('ceiling:enter', onCeilingEnter)
     emitter.on('ceiling:move', onCeilingMove)
     emitter.on('ceiling:click', onCeilingClick)
@@ -1694,6 +1845,10 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
       emitter.off('wall:move', onWallMove)
       emitter.off('wall:click', onWallClick)
       emitter.off('wall:leave', onWallLeave)
+      emitter.off('roof:enter', onRoofWallEnter)
+      emitter.off('roof:move', onRoofWallMove)
+      emitter.off('roof:click', onRoofWallClick)
+      emitter.off('roof:leave', onRoofWallLeave)
       emitter.off('ceiling:enter', onCeilingEnter)
       emitter.off('ceiling:move', onCeilingMove)
       emitter.off('ceiling:click', onCeilingClick)

packages/editor/src/components/tools/select/box-select-state.ts

@@ -9,6 +9,10 @@ type PointerEventLike = {
   nativeEvent?: PointerEvent | PointerEventLike
 }
 
+type SuppressBoxSelectOptions = {
+  markHandled?: boolean
+}
+
 function pointerIdFor(event: PointerEvent | PointerEventLike): number | null {
   if ('pointerId' in event && typeof event.pointerId === 'number') {
     return event.pointerId
@@ -28,8 +32,12 @@ export function markBoxSelectHandled() {
   }, 50)
 }
 
-export function suppressBoxSelectForPointer(event: PointerEvent | PointerEventLike) {
-  markBoxSelectHandled()
+export function suppressBoxSelectForPointer(
+  event: PointerEvent | PointerEventLike,
+  options: SuppressBoxSelectOptions = {},
+) {
+  const markHandled = options.markHandled ?? true
+  if (markHandled) markBoxSelectHandled()
 
   const pointerId = pointerIdFor(event)
   if (pointerId === null || suppressedPointerIds.has(pointerId)) return
@@ -38,7 +46,7 @@ export function suppressBoxSelectForPointer(event: PointerEvent | PointerEventLi
 
   const clear = (releaseEvent?: PointerEvent) => {
     if (releaseEvent && releaseEvent.pointerId !== pointerId) return
-    markBoxSelectHandled()
+    if (markHandled) markBoxSelectHandled()
     suppressedPointerIds.delete(pointerId)
     const cleanup = suppressionCleanups.get(pointerId)
     suppressionCleanups.delete(pointerId)
@@ -48,15 +56,18 @@ export function suppressBoxSelectForPointer(event: PointerEvent | PointerEventLi
   const onPointerUp = (releaseEvent: PointerEvent) => clear(releaseEvent)
   const onPointerCancel = (releaseEvent: PointerEvent) => clear(releaseEvent)
   const onBlur = () => clear()
+  // Click-preserving handle interactions need suppression cleared before
+  // canvas-level pointerup handlers decide whether to block the follow-up click.
+  const releaseListenerOptions = markHandled ? undefined : { capture: true }
   const cleanup = () => {
-    window.removeEventListener('pointerup', onPointerUp)
-    window.removeEventListener('pointercancel', onPointerCancel)
+    window.removeEventListener('pointerup', onPointerUp, releaseListenerOptions)
+    window.removeEventListener('pointercancel', onPointerCancel, releaseListenerOptions)
     window.removeEventListener('blur', onBlur)
   }
 
   suppressionCleanups.set(pointerId, cleanup)
-  window.addEventListener('pointerup', onPointerUp)
-  window.addEventListener('pointercancel', onPointerCancel)
+  window.addEventListener('pointerup', onPointerUp, releaseListenerOptions)
+  window.addEventListener('pointercancel', onPointerCancel, releaseListenerOptions)
   window.addEventListener('blur', onBlur)
 }
 

packages/editor/src/components/tools/shared/polygon-editor.tsx

@@ -3,9 +3,11 @@ import { SCENE_LAYER, useViewer } from '@pascal-app/viewer'
 import { createPortal, type ThreeEvent } from '@react-three/fiber'
 import { Fragment, useCallback, useEffect, useMemo, useRef, useState } from 'react'
 import {
+  BoxGeometry,
   BufferGeometry,
   Color,
   CylinderGeometry,
+  DoubleSide,
   ExtrudeGeometry,
   Float32BufferAttribute,
   type Line,
@@ -20,10 +22,10 @@ import {
   ARROW_COLOR as EDGE_ARROW_COLOR,
   ARROW_HOVER_COLOR as EDGE_ARROW_HOVER_COLOR,
   ARROW_SCALE as EDGE_ARROW_SCALE,
-  useArrowMaterial,
   useInvisibleHitAreaMaterial,
 } from '../../editor/node-arrow-handles'
 import { snapToHalf } from '../item/placement-math'
+import { suppressBoxSelectForPointer } from '../select/box-select-state'
 
 const Y_OFFSET = 0.02
 // Per-side resize arrows: indigo chevrons that match the registry arrow
@@ -77,6 +79,17 @@ type DragState = {
   pointerId: number
 }
 
+export type PolygonEditorPlanPointSnapContext = {
+  rawPoint: [number, number]
+  gridPoint: [number, number]
+  mode: DragState['mode']
+  vertexIndex: number | null
+  edgeIndex?: number
+  initialPosition: [number, number]
+  initialPolygon: Array<[number, number]>
+  nativeEvent?: GridEvent['nativeEvent']
+}
+
 export interface PolygonEditorProps {
   polygon: Array<[number, number]>
   color?: string
@@ -104,6 +117,8 @@ export interface PolygonEditorProps {
   onVertexHoverChange?: (vertexIndex: number | null) => void
   /** Called when a midpoint add-vertex handle enters or leaves hover. */
   onMidpointHoverChange?: (edgeIndex: number | null) => void
+  /** Called when an edge move handle enters or leaves hover. */
+  onEdgeHoverChange?: (edgeIndex: number | null) => void
   /** Called when any polygon drag starts or ends. */
   onDragStateChange?: (isDragging: boolean) => void
   /** Called once when a polygon drag starts. */
@@ -114,6 +129,10 @@ export interface PolygonEditorProps {
   showBorderLine?: boolean
   /** Whether midpoint handles can add new vertices. */
   showMidpointHandles?: boolean
+  /** Whether hovering a handle should also tint its connected edges and endpoint handles. */
+  highlightConnectedHandles?: boolean
+  /** Optional host-owned point snapper. Defaults to the existing half-grid snap. */
+  resolvePlanPoint?: (context: PolygonEditorPlanPointSnapContext) => [number, number]
   /** Optional vertex handle renderer for host-specific affordances. */
   renderVertexHandle?: PolygonVertexHandleRenderer
   /** Optional midpoint handle renderer for host-specific add-vertex affordances. */
@@ -127,6 +146,7 @@ export interface PolygonEditorProps {
 const MIN_HANDLE_HEIGHT = 0.15
 const EDGE_HANDLE_HEIGHT = 0.06
 const EDGE_HANDLE_THICKNESS = 0.12
+const EDGE_HANDLE_GEOMETRY = new BoxGeometry(1, 1, 1)
 
 function getEdgeNormal(start: [number, number], end: [number, number]): [number, number] | null {
   const dx = end[0] - start[0]
@@ -137,6 +157,11 @@ function getEdgeNormal(start: [number, number], end: [number, number]): [number,
   return [-dz / length, dx / length]
 }
 
+function stopHandlePointerDown(event: ThreeEvent<PointerEvent>) {
+  event.stopPropagation()
+  suppressBoxSelectForPointer(event, { markHandled: false })
+}
+
 type HandleClickHandler = (event: ThreeEvent<MouseEvent>) => void
 type HandlePointerHandler = (event: ThreeEvent<PointerEvent>) => void
 
@@ -181,7 +206,7 @@ function usePolygonNodeMaterial(color: string, opacity = 1): MeshBasicNodeMateri
     () =>
       new MeshBasicNodeMaterial({
         color: new Color('#ffffff'),
-        depthTest: false,
+        depthTest: true,
         depthWrite: true,
         opacity: 1,
         transparent: true,
@@ -198,11 +223,24 @@ function usePolygonNodeMaterial(color: string, opacity = 1): MeshBasicNodeMateri
   return material
 }
 
+function usePolygonArrowMaterial(): MeshBasicNodeMaterial {
+  return useMemo(
+    () =>
+      new MeshBasicNodeMaterial({
+        color: new Color(EDGE_ARROW_COLOR),
+        depthTest: true,
+        depthWrite: true,
+        opacity: 1,
+        side: DoubleSide,
+        transparent: true,
+      }),
+    [],
+  )
+}
+
 // One mesh per handle: lives on SCENE_LAYER with a node material so the
-// post-processing ink-edge pass outlines it, and carries the pointer handlers
-// directly so it stays grabbable — matching the registry arrow gizmos in
-// node-arrow-handles.tsx. No paired hit mesh is needed; the R3F event
-// raycaster picks SCENE_LAYER meshes too.
+// post-processing ink-edge pass outlines it. The visual material still
+// depth-tests, so walls/items in front can occlude it.
 function OutlinedCylinderHandle({
   radius,
   height,
@@ -290,7 +328,7 @@ function OutlinedEdgeArrowHandle({
   rotationY: number
   scale: number
 } & PolygonHandleHandlers) {
-  const material = useArrowMaterial()
+  const material = usePolygonArrowMaterial()
   useEffect(() => {
     material.color.set(color)
   }, [color, material])
@@ -311,6 +349,47 @@ function OutlinedEdgeArrowHandle({
   )
 }
 
+function HighlightedEdgeSegment({
+  end,
+  start,
+  y,
+}: {
+  end: [number, number]
+  start: [number, number]
+  y: number
+}) {
+  const geometry = useMemo(() => {
+    const nextGeometry = new BufferGeometry()
+    nextGeometry.setAttribute(
+      'position',
+      new Float32BufferAttribute([start[0], y, start[1], end[0], y, end[1]], 3),
+    )
+    return nextGeometry
+  }, [end, start, y])
+
+  useEffect(() => () => geometry.dispose(), [geometry])
+
+  return (
+    <line
+      // @ts-expect-error R3F <line> element conflicts with SVG <line> type
+      frustumCulled={false}
+      geometry={geometry}
+      layers={EDITOR_LAYER}
+      raycast={NO_RAYCAST}
+      renderOrder={12}
+    >
+      <lineBasicNodeMaterial
+        color={EDGE_ARROW_HOVER_COLOR}
+        depthTest
+        depthWrite={false}
+        linewidth={4}
+        opacity={0.95}
+        transparent
+      />
+    </line>
+  )
+}
+
 export const PolygonEditor: React.FC<PolygonEditorProps> = ({
   polygon,
   color = '#3b82f6',
@@ -324,11 +403,14 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
   onBeforeVertexDrag,
   onVertexHoverChange,
   onMidpointHoverChange,
+  onEdgeHoverChange,
   onDragStateChange,
   onDragStart,
   onDragCommit,
   showBorderLine = true,
   showMidpointHandles = true,
+  highlightConnectedHandles = false,
+  resolvePlanPoint,
   renderMidpointHandle,
   renderVertexHandle,
 }) => {
@@ -429,6 +511,12 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
 
   useEffect(() => () => onMidpointHoverChange?.(null), [onMidpointHoverChange])
 
+  useEffect(() => {
+    onEdgeHoverChange?.(hoveredEdge)
+  }, [hoveredEdge, onEdgeHoverChange])
+
+  useEffect(() => () => onEdgeHoverChange?.(null), [onEdgeHoverChange])
+
   const lineRef = useRef<Line>(null!)
   const previousPositionRef = useRef<[number, number] | null>(null)
 
@@ -556,6 +644,47 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
     })
   }, [displayPolygon])
 
+  const activeVertexIndex = dragState?.mode === 'vertex' ? dragState.vertexIndex : hoveredVertex
+  const activeEdgeIndex = dragState?.mode === 'edge' ? dragState.edgeIndex : hoveredEdge
+
+  const highlightedEdgeIndices = useMemo(() => {
+    const next = new Set<number>()
+    const edgeCount = displayPolygon.length
+    if (!highlightConnectedHandles || edgeCount < 2) return next
+
+    if (activeVertexIndex !== null && activeVertexIndex !== undefined) {
+      next.add(activeVertexIndex)
+      next.add((activeVertexIndex - 1 + edgeCount) % edgeCount)
+    }
+    if (hoveredMidpoint !== null) {
+      next.add(hoveredMidpoint)
+    }
+    if (activeEdgeIndex !== null && activeEdgeIndex !== undefined) {
+      next.add(activeEdgeIndex)
+    }
+
+    return next
+  }, [
+    activeEdgeIndex,
+    activeVertexIndex,
+    displayPolygon.length,
+    highlightConnectedHandles,
+    hoveredMidpoint,
+  ])
+
+  const isVertexLinkedHighlighted = useCallback(
+    (index: number) => {
+      if (!highlightConnectedHandles || highlightedEdgeIndices.size === 0) return false
+      const edgeCount = displayPolygon.length
+      if (edgeCount < 2) return false
+      return (
+        highlightedEdgeIndices.has(index) ||
+        highlightedEdgeIndices.has((index - 1 + edgeCount) % edgeCount)
+      )
+    },
+    [displayPolygon.length, highlightConnectedHandles, highlightedEdgeIndices],
+  )
+
   const arrowGeometry = useMemo(() => createEdgeArrowGeometry(), [])
   useEffect(() => () => arrowGeometry.dispose(), [arrowGeometry])
 
@@ -616,9 +745,21 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
   useEffect(() => {
     const onGridMove = (event: GridEvent) => {
       const point = levelNode ? event.localPosition : event.position
-      const gridX = snapToHalf(point[0])
-      const gridZ = snapToHalf(point[2])
-      const newPosition: [number, number] = [gridX, gridZ]
+      const rawPoint: [number, number] = [point[0], point[2]]
+      const gridPoint: [number, number] = [snapToHalf(rawPoint[0]), snapToHalf(rawPoint[1])]
+      const newPosition =
+        dragState?.isDragging && resolvePlanPoint
+          ? resolvePlanPoint({
+              rawPoint,
+              gridPoint,
+              mode: dragState.mode,
+              vertexIndex: dragState.vertexIndex,
+              edgeIndex: dragState.edgeIndex,
+              initialPosition: dragState.initialPosition,
+              initialPolygon: dragState.initialPolygon,
+              nativeEvent: event.nativeEvent,
+            })
+          : gridPoint
 
       // Play snap sound when cursor moves to a new grid cell during drag
       if (
@@ -673,7 +814,7 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
     return () => {
       emitter.off('grid:move', onGridMove)
     }
-  }, [dragState, handleVertexDrag, levelNode, updatePreviewPolygon])
+  }, [dragState, handleVertexDrag, levelNode, resolvePlanPoint, updatePreviewPolygon])
 
   // Set up pointer up listener for ending drag
   useEffect(() => {
@@ -741,9 +882,9 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
   const handleHeight = Math.max(MIN_HANDLE_HEIGHT, surfaceHeight + 0.02)
   const edgeHandleY = editY + handleHeight - EDGE_HANDLE_HEIGHT / 2
 
-  // Interactive handles are single SCENE_LAYER node-material meshes (like the
-  // registry arrow gizmos) so the ink-edge pass outlines them while they stay
-  // grabbable. The edge BAR and border line stay on EDITOR_LAYER, visual-only
+  // Interactive handles are SCENE_LAYER node-material meshes so the ink-edge
+  // pass outlines them while normal scene depth can hide them. The edge BAR and
+  // border line stay on EDITOR_LAYER, visual-only
   // (raycast disabled) so they never steal clicks from the vertex/midpoint
   // handles overlapping them — edge dragging starts from the chevron arrow
   // outside the polygon edge.
@@ -771,10 +912,28 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
         </line>
       )}
 
+      {highlightConnectedHandles &&
+        highlightedEdgeIndices.size > 0 &&
+        Array.from(highlightedEdgeIndices).map((edgeIndex) => {
+          const start = displayPolygon[edgeIndex]
+          const end = displayPolygon[(edgeIndex + 1) % displayPolygon.length]
+          if (!(start && end)) return null
+          return (
+            <HighlightedEdgeSegment
+              end={end}
+              key={`highlight-edge-${edgeIndex}`}
+              start={start}
+              y={edgeHandleY}
+            />
+          )
+        })}
+
       {/* Vertex handles - blue cylinders that match surface height */}
       {displayPolygon.map(([x, z], index) => {
         const isHovered = hoveredVertex === index
         const isDragging = dragState?.mode === 'vertex' && dragState.vertexIndex === index
+        const isLinkedHighlighted = isVertexLinkedHighlighted(index)
+        const isHighlighted = isDragging || isHovered || isLinkedHighlighted
         const radius = 0.1
         const height = handleHeight
         const point: [number, number] = [x!, z!]
@@ -793,7 +952,7 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
           },
           onPointerDown: (e) => {
             if (e.button !== 0) return
-            e.stopPropagation()
+            stopHandlePointerDown(e)
             setHoveredEdge(null)
             onBeforeVertexDrag?.(index, point)
             startDrag({
@@ -835,7 +994,7 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
 
         return (
           <OutlinedCylinderHandle
-            color={isDragging || isHovered ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR}
+            color={isHighlighted ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR}
             height={height}
             key={`vertex-${index}`}
             {...handleProps}
@@ -854,7 +1013,7 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
           }}
           onPointerDown={(e) => {
             if (e.button !== 0) return
-            e.stopPropagation()
+            stopHandlePointerDown(e)
             setHoveredEdge(null)
             startDrag({
               isDragging: true,
@@ -873,6 +1032,8 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
         edgeHandles.map(({ index, length, midpoint, rotationY, outwardNormal, outwardAngle }) => {
           const isHovered = hoveredEdge === index
           const isDragging = dragState?.mode === 'edge' && dragState.edgeIndex === index
+          const isLinkedHighlighted = highlightedEdgeIndices.has(index)
+          const isHighlighted = isDragging || isHovered || isLinkedHighlighted
           const arrowX = midpoint[0] + outwardNormal[0] * EDGE_ARROW_OFFSET
           const arrowZ = midpoint[1] + outwardNormal[1] * EDGE_ARROW_OFFSET
 
@@ -906,15 +1067,16 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
                   which sits outside the polygon and never overlaps a
                   vertex/midpoint handle. */}
               <mesh
+                geometry={EDGE_HANDLE_GEOMETRY}
                 layers={EDITOR_LAYER}
                 position={[midpoint[0], edgeHandleY, midpoint[1]]}
                 raycast={NO_RAYCAST}
                 rotation={[0, rotationY, 0]}
+                scale={[length, EDGE_HANDLE_HEIGHT, EDGE_HANDLE_THICKNESS]}
               >
-                <boxGeometry args={[length, EDGE_HANDLE_HEIGHT, EDGE_HANDLE_THICKNESS]} />
                 <meshBasicMaterial
-                  color={isDragging ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR}
-                  opacity={isDragging ? 0.5 : isHovered ? 0.38 : 0.14}
+                  color={isHighlighted ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR}
+                  opacity={isDragging ? 0.5 : isHighlighted ? 0.38 : 0.14}
                   transparent
                 />
               </mesh>
@@ -922,7 +1084,7 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
                   Points outward from the edge; dragging it translates only this
                   edge's two vertices along the outward normal. */}
               <OutlinedEdgeArrowHandle
-                color={isDragging || isHovered ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR}
+                color={isHighlighted ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR}
                 geometry={arrowGeometry}
                 onClick={(e) => {
                   if (e.button !== 0) return
@@ -930,7 +1092,7 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
                 }}
                 onPointerDown={(e) => {
                   if (e.button !== 0) return
-                  e.stopPropagation()
+                  stopHandlePointerDown(e)
                   beginEdgeDrag(e)
                 }}
                 onPointerEnter={(e) => {
@@ -954,6 +1116,8 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
         !dragState &&
         midpoints.map(([x, z], index) => {
           const isHovered = hoveredMidpoint === index
+          const isLinkedHighlighted = highlightedEdgeIndices.has(index)
+          const isHighlighted = isHovered || isLinkedHighlighted
           const radius = 0.06
           const height = handleHeight
           const point: [number, number] = [x!, z!]
@@ -965,7 +1129,7 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
             },
             onPointerDown: (e) => {
               if (e.button !== 0) return
-              e.stopPropagation()
+              stopHandlePointerDown(e)
               onBeforeVertexDrag?.(index + 1, point)
               const insertedVertex = handleAddVertex(index, point)
               if (insertedVertex.vertexIndex >= 0) {
@@ -1008,11 +1172,11 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
 
           return (
             <OutlinedCylinderHandle
-              color={isHovered ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR}
+              color={isHighlighted ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR}
               height={height}
               key={`midpoint-${index}`}
               {...handleProps}
-              opacity={isHovered ? 1 : 0.7}
+              opacity={isHighlighted ? 1 : 0.7}
               position={position}
               radius={radius}
             />

packages/editor/src/components/tools/site/site-boundary-editor.tsx

@@ -3,7 +3,15 @@ import { SCENE_LAYER } from '@pascal-app/viewer'
 import { useGLTF } from '@react-three/drei/core/Gltf'
 import { useFrame } from '@react-three/fiber'
 import { Suspense, useCallback, useEffect, useMemo, useRef, useState } from 'react'
-import { Color, CylinderGeometry, DoubleSide, type Mesh, type Object3D, RingGeometry } from 'three'
+import {
+  Color,
+  CylinderGeometry,
+  DoubleSide,
+  type Group,
+  type Mesh,
+  type Object3D,
+  RingGeometry,
+} from 'three'
 import { MeshBasicNodeMaterial } from 'three/webgpu'
 import { EDITOR_LAYER } from '../../../lib/constants'
 import { sfxEmitter } from '../../../lib/sfx-bus'
@@ -38,6 +46,7 @@ const SITE_FLAG_HALO_COLOR = '#6366f1'
 
 type TintableMaterial = {
   color?: Color
+  depthTest: boolean
   depthWrite: boolean
   opacity: number
   needsUpdate: boolean
@@ -69,10 +78,9 @@ function SiteFlagModel({
         mesh.frustumCulled = false
         mesh.raycast = NO_RAYCAST
         mesh.receiveShadow = false
-        mesh.renderOrder = 1010
         mesh.material = new MeshBasicNodeMaterial({
           color: new Color(ARROW_COLOR),
-          depthTest: false,
+          depthTest: true,
           depthWrite: opacity >= 0.999,
           opacity,
           transparent: opacity < 0.999,
@@ -93,6 +101,7 @@ function SiteFlagModel({
 
         for (const material of materials as Array<MeshBasicNodeMaterial & TintableMaterial>) {
           material.color?.copy(color)
+          material.depthTest = true
           material.opacity = opacity
           material.transparent = opacity < 0.999
           material.depthWrite = opacity >= 0.999
@@ -217,11 +226,23 @@ function SiteFlagFallback({
     <group position={[0, SITE_FLAG_BASE_Y + (active ? SITE_FLAG_ACTIVE_LIFT : 0), 0]}>
       <mesh layers={SCENE_LAYER} position={[0, 0.16, 0]} raycast={NO_RAYCAST}>
         <cylinderGeometry args={[0.11, 0.16, 0.32, 24]} />
-        <meshBasicMaterial color={color} depthTest={false} opacity={opacity} transparent />
+        <meshBasicMaterial
+          color={color}
+          depthTest
+          depthWrite={opacity >= 0.999}
+          opacity={opacity}
+          transparent={opacity < 0.999}
+        />
       </mesh>
       <mesh layers={SCENE_LAYER} position={[0, 0.34, 0]} raycast={NO_RAYCAST}>
         <cylinderGeometry args={[0.04, 0.11, 0.14, 24]} />
-        <meshBasicMaterial color={color} depthTest={false} opacity={opacity} transparent />
+        <meshBasicMaterial
+          color={color}
+          depthTest
+          depthWrite={opacity >= 0.999}
+          opacity={opacity}
+          transparent={opacity < 0.999}
+        />
       </mesh>
     </group>
   )
@@ -394,6 +415,26 @@ export const SiteBoundaryEditor: React.FC = () => {
     }
   }, [isSiteEditing, siteId])
 
+  // The flag models render on SCENE_LAYER (scene-depth occlusion), so unlike
+  // EDITOR_LAYER affordances the thumbnail camera can't filter them — hide
+  // them around captures (preset/snapshot/auto-save thumbnails), same as
+  // `handle-arrow.tsx`.
+  const handlesRootRef = useRef<Group>(null)
+  useEffect(() => {
+    const hideForCapture = () => {
+      if (handlesRootRef.current) handlesRootRef.current.visible = false
+    }
+    const restoreAfterCapture = () => {
+      if (handlesRootRef.current) handlesRootRef.current.visible = true
+    }
+    emitter.on('thumbnail:before-capture', hideForCapture)
+    emitter.on('thumbnail:after-capture', restoreAfterCapture)
+    return () => {
+      emitter.off('thumbnail:before-capture', hideForCapture)
+      emitter.off('thumbnail:after-capture', restoreAfterCapture)
+    }
+  }, [])
+
   const activateSiteEditing = useCallback(() => {
     isDraggingSiteBoundaryRef.current = true
     setIsDraggingSiteBoundary(true)
@@ -470,6 +511,7 @@ export const SiteBoundaryEditor: React.FC = () => {
   if (!showSiteHandles) return null
 
   return (
+    <group ref={handlesRootRef}>
       <PolygonEditor
         color={isSiteBoundaryHighlighted ? ARROW_COLOR : '#10b981'}
         minVertices={3}
@@ -490,5 +532,6 @@ export const SiteBoundaryEditor: React.FC = () => {
         showBorderLine={isSiteBoundaryHighlighted}
         showMidpointHandles={showSiteHandles}
       />
+    </group>
   )
 }

packages/editor/src/components/tools/wall/wall-drafting.ts

@@ -20,6 +20,7 @@ import {
   WALL_JOIN_SNAP_RADIUS,
   type WallDraftSnapResult,
   type WallPlanPoint,
+  type WallSnapRadii,
 } from './wall-snap-geometry'
 
 // The pure snap geometry lives in `./wall-snap-geometry`; re-exported here so
@@ -30,6 +31,7 @@ export {
   type WallDraftSnapKind,
   type WallDraftSnapResult,
   type WallPlanPoint,
+  type WallSnapRadii,
 } from './wall-snap-geometry'
 
 export const WALL_GRID_STEP = 0.5
@@ -345,6 +347,8 @@ type SnapWallDraftArgs = {
    * local-axis grid at `step`.
    */
   gridSnap?: (point: WallPlanPoint) => WallPlanPoint
+  /** Optional magnetic snap radii. Omitted means wall tools keep their defaults. */
+  snapRadii?: WallSnapRadii
 }
 
 export function snapWallDraftPointDetailed(args: SnapWallDraftArgs): WallDraftSnapResult {
@@ -357,13 +361,14 @@ export function snapWallDraftPointDetailed(args: SnapWallDraftArgs): WallDraftSn
     step: overrideStep,
     magnetic = true,
     gridSnap,
+    snapRadii,
   } = args
 
   // Discrete special points (corner / midpoint / crossing) are taken from the
   // raw cursor so an interim grid snap can't mask them. A corner always wins,
   // then the nearer of midpoint / crossing — see `findWallSpecialPointSnap`.
   if (magnetic) {
-    const special = findWallSpecialPointSnap(point, walls, ignoreWallIds)
+    const special = findWallSpecialPointSnap(point, walls, ignoreWallIds, snapRadii)
     if (special) return special
   }
 
@@ -377,7 +382,10 @@ export function snapWallDraftPointDetailed(args: SnapWallDraftArgs): WallDraftSn
         : snapPointToGrid(point, step)
 
   if (magnetic) {
-    const wallSnap = findWallSnapTarget(basePoint, walls, { ignoreWallIds })
+    const wallSnap = findWallSnapTarget(basePoint, walls, {
+      ignoreWallIds,
+      radius: snapRadii?.wall,
+    })
     if (wallSnap) return { point: wallSnap, snap: 'wall' }
   }
 

packages/editor/src/components/tools/wall/wall-snap-geometry.test.ts

@@ -62,6 +62,13 @@ describe('findWallSpecialPointSnap', () => {
     // handled separately by findWallSnapTarget, not a special point.
     expect(findWallSpecialPointSnap([1.2, 0.1], walls)).toBeNull()
   })
+
+  test('honors tighter per-call radii without changing defaults', () => {
+    const walls = [makeWall([0, 0], [4, 0])]
+
+    expect(findWallSpecialPointSnap([0.34, 0], walls)?.snap).toBe('endpoint')
+    expect(findWallSpecialPointSnap([0.34, 0], walls, undefined, { endpoint: 0.3 })).toBeNull()
+  })
 })
 
 describe('findWallSnapTarget (edge / along-wall)', () => {
@@ -76,4 +83,10 @@ describe('findWallSnapTarget (edge / along-wall)', () => {
     const walls = [makeWall([0, 0], [4, 0])]
     expect(findWallSnapTarget([1.2, 2], walls)).toBeNull()
   })
+
+  test('honors a tighter wall-body radius', () => {
+    const walls = [makeWall([0, 0], [4, 0])]
+
+    expect(findWallSnapTarget([1.2, 0.1], walls, { radius: 0.08 })).toBeNull()
+  })
 })

packages/editor/src/components/tools/wall/wall-snap-geometry.ts

@@ -15,6 +15,8 @@ export type WallPlanPoint = [number, number]
 /** Which kind of existing-geometry snap produced a drafted point. */
 export type WallDraftSnapKind = 'endpoint' | 'midpoint' | 'intersection' | 'wall'
 
+export type WallSnapRadii = Partial<Record<WallDraftSnapKind, number>>
+
 export type WallDraftSnapResult = {
   point: WallPlanPoint
   /**
@@ -119,9 +121,10 @@ export function findWallEndpointFromRaw(
   point: WallPlanPoint,
   walls: WallNode[],
   ignoreWallIds?: string[],
+  radius = WALL_ENDPOINT_SNAP_RADIUS,
 ): WallPlanPoint | null {
   const ignored = new Set(ignoreWallIds ?? [])
-  const radiusSquared = WALL_ENDPOINT_SNAP_RADIUS ** 2
+  const radiusSquared = radius ** 2
   let best: WallPlanPoint | null = null
   let bestDistSq = Number.POSITIVE_INFINITY
 
@@ -152,9 +155,10 @@ export function findWallMidpointFromRaw(
   point: WallPlanPoint,
   walls: WallNode[],
   ignoreWallIds?: string[],
+  radius = WALL_MIDPOINT_SNAP_RADIUS,
 ): WallPlanPoint | null {
   const ignored = new Set(ignoreWallIds ?? [])
-  const radiusSquared = WALL_MIDPOINT_SNAP_RADIUS ** 2
+  const radiusSquared = radius ** 2
   let best: WallPlanPoint | null = null
   let bestDistSq = Number.POSITIVE_INFINITY
 
@@ -202,10 +206,11 @@ export function findWallIntersectionFromRaw(
   point: WallPlanPoint,
   walls: WallNode[],
   ignoreWallIds?: string[],
+  radius = WALL_INTERSECTION_SNAP_RADIUS,
 ): WallPlanPoint | null {
   const ignored = new Set(ignoreWallIds ?? [])
   const straight = walls.filter((wall) => !ignored.has(wall.id) && !isCurvedWall(wall))
-  const radiusSquared = WALL_INTERSECTION_SNAP_RADIUS ** 2
+  const radiusSquared = radius ** 2
   let best: WallPlanPoint | null = null
   let bestDistSq = Number.POSITIVE_INFINITY
 
@@ -257,12 +262,13 @@ export function findWallSpecialPointSnap(
   point: WallPlanPoint,
   walls: WallNode[],
   ignoreWallIds?: string[],
+  radii?: WallSnapRadii,
 ): WallDraftSnapResult | null {
-  const endpoint = findWallEndpointFromRaw(point, walls, ignoreWallIds)
+  const endpoint = findWallEndpointFromRaw(point, walls, ignoreWallIds, radii?.endpoint)
   if (endpoint) return { point: endpoint, snap: 'endpoint' }
 
-  const midpoint = findWallMidpointFromRaw(point, walls, ignoreWallIds)
-  const intersection = findWallIntersectionFromRaw(point, walls, ignoreWallIds)
+  const midpoint = findWallMidpointFromRaw(point, walls, ignoreWallIds, radii?.midpoint)
+  const intersection = findWallIntersectionFromRaw(point, walls, ignoreWallIds, radii?.intersection)
   return nearestCandidate(point, [
     midpoint && { point: midpoint, snap: 'midpoint' },
     intersection && { point: intersection, snap: 'intersection' },

packages/editor/src/components/ui/action-menu/control-modes.tsx

@@ -1,15 +1,13 @@
 'use client'
 
 import { Icon } from '@iconify/react'
-import { type LevelNode, useScene } from '@pascal-app/core'
-import { useViewer } from '@pascal-app/viewer'
 import { type LucideIcon, Trash2 } from 'lucide-react'
 import Image from 'next/image'
 import { cn } from './../../../lib/utils'
-import useEditor, { selectSiteFloorplanContext } from './../../../store/use-editor'
+import useEditor from './../../../store/use-editor'
 import { ActionButton } from './action-button'
 
-type ControlId = 'select' | 'box-select' | 'site-edit' | 'zone' | 'delete'
+type ControlId = 'select' | 'box-select' | 'zone' | 'delete'
 
 type ControlConfig = {
   id: ControlId
@@ -32,13 +30,6 @@ const controls: ControlConfig[] = [
     color: 'hover:bg-blue-500/20 hover:text-blue-400',
     activeColor: 'bg-blue-500/20 text-blue-400',
   },
-  {
-    id: 'site-edit',
-    imageSrc: '/icons/site-flag.png',
-    label: 'Edit site',
-    color: 'hover:bg-white/5',
-    activeColor: 'bg-white/10 hover:bg-white/10',
-  },
   {
     id: 'zone',
     imageSrc: '/icons/zone.png',
@@ -65,47 +56,20 @@ export function ControlModes() {
   const setPhase = useEditor((state) => state.setPhase)
   const setStructureLayer = useEditor((state) => state.setStructureLayer)
   const setSelectionTool = useEditor((state) => state.setFloorplanSelectionTool)
-  const levelId = useViewer((s) => s.selection.levelId)
-
-  // Only subscribe to the primitive `level` number — when walls are added to
-  // this level the object ref changes but this number doesn't, so Object.is
-  // dedupes and we avoid a re-render.
-  const levelIndex = useScene((state) => {
-    if (!levelId) return null
-    const node = state.nodes[levelId]
-    return node?.type === 'level' ? (node as LevelNode).level : null
-  })
 
   const isSiteEditing = phase === 'site'
-  const isGroundFloor = levelIndex === 0
-  const canEnterSiteEdit = isGroundFloor || isSiteEditing
 
   const structureLayer = useEditor((state) => state.structureLayer)
 
   const getIsActive = (id: ControlId): boolean => {
-    if (isSiteEditing) return id === 'site-edit'
     if (id === 'select') return mode === 'select' && selectionTool === 'click'
     if (id === 'box-select') return mode === 'select' && selectionTool === 'marquee'
-    if (id === 'site-edit') return false
     if (id === 'zone')
       return mode === 'build' && phase === 'structure' && structureLayer === 'zones'
     return mode === id
   }
 
   const handleClick = (id: ControlId) => {
-    if (id === 'site-edit') {
-      if (isSiteEditing) {
-        // Toggle off → back to structure/select
-        setPhase('structure')
-        setMode('select')
-        setStructureLayer('elements')
-      } else if (isGroundFloor) {
-        useEditor.setState({ phase: 'site', mode: 'select', tool: null, catalogCategory: null })
-        selectSiteFloorplanContext()
-      }
-      return
-    }
-
     // Exit site editing first if needed
     if (isSiteEditing) {
       setPhase('structure')
@@ -136,36 +100,19 @@ export function ControlModes() {
       {controls.map((c) => {
         const ModeIcon = c.icon
         const isImageMode = Boolean(c.imageSrc)
-        const isSiteButton = c.id === 'site-edit'
         const isActive = getIsActive(c.id)
-        const isDisabled = isSiteButton && !canEnterSiteEdit
 
         return (
           <ActionButton
             className={cn(
               'group text-muted-foreground',
-              isSiteButton
-                ? isActive
-                  ? c.activeColor
-                  : canEnterSiteEdit
-                    ? 'opacity-60 grayscale hover:bg-white/5 hover:opacity-100 hover:grayscale-0'
-                    : 'cursor-not-allowed opacity-35 grayscale'
-                : !(isImageMode || isActive) && c.color,
-              !(isSiteButton || isImageMode) && isActive && c.activeColor,
-              !isSiteButton && isImageMode && isActive && 'bg-white/10 hover:bg-white/10',
-              !isSiteButton && isImageMode && !isActive && 'hover:bg-white/5',
+              !(isImageMode || isActive) && c.color,
+              !isImageMode && isActive && c.activeColor,
+              isImageMode && isActive && 'bg-white/10 hover:bg-white/10',
+              isImageMode && !isActive && 'hover:bg-white/5',
             )}
-            disabled={isDisabled}
             key={c.id}
-            label={
-              isSiteButton
-                ? isActive
-                  ? 'Exit site editing'
-                  : canEnterSiteEdit
-                    ? 'Edit site'
-                    : 'Site editing (ground level only)'
-                : c.label
-            }
+            label={c.label}
             onClick={() => handleClick(c.id)}
             shortcut={c.shortcut}
             size="icon"
@@ -176,11 +123,7 @@ export function ControlModes() {
                 alt={c.label}
                 className={cn(
                   'h-[28px] w-[28px] object-contain transition-[opacity,filter] duration-200',
-                  isSiteButton
-                    ? isActive
-                      ? 'opacity-100 grayscale-0'
-                      : ''
-                    : isActive
+                  isActive
                     ? 'opacity-100 grayscale-0'
                     : 'opacity-60 grayscale group-hover:opacity-100 group-hover:grayscale-0',
                 )}

packages/editor/src/components/ui/action-menu/view-toggles.tsx

@@ -26,6 +26,8 @@ import { ActionButton } from './action-button'
 const MAX_FILE_SIZE = 200 * 1024 * 1024 // 200MB
 const ACCEPTED_FILE_TYPES = '.glb,.gltf,image/jpeg,image/png,image/webp,image/gif'
 const GRID_SNAP_STEPS: GridSnapStep[] = [0.5, 0.25, 0.1, 0.05]
+const REFERENCES_EMPTY_TEXT =
+  'Upload GLB meshes as scan references or blueprint images as guide references.'
 
 function formatGridSnapStep(step: GridSnapStep) {
   return step.toFixed(2)
@@ -342,7 +344,7 @@ function GuidesControl() {
             </div>
           ) : (
             <div className="rounded-xl border border-border/45 border-dashed bg-background/60 px-3 py-4 text-muted-foreground text-sm">
-              No guide images on this level yet.
+              {REFERENCES_EMPTY_TEXT}
             </div>
           )}
         </div>
@@ -581,7 +583,7 @@ function ScansControl() {
             </div>
           ) : (
             <div className="rounded-xl border border-border/45 border-dashed bg-background/60 px-3 py-4 text-muted-foreground text-sm">
-              No scans on this level yet.
+              {REFERENCES_EMPTY_TEXT}
             </div>
           )}
         </div>
@@ -805,7 +807,7 @@ function ReferencesControl() {
             </div>
           )}
           <ReferenceListSection
-            emptyText="No scans on this level yet."
+            emptyText={REFERENCES_EMPTY_TEXT}
             iconSrc="/icons/mesh.png"
             nodes={scans}
             noun="scan"
@@ -816,7 +818,7 @@ function ReferencesControl() {
           />
           <div className="h-px bg-border/45" />
           <ReferenceListSection
-            emptyText="No guide images on this level yet."
+            emptyText={REFERENCES_EMPTY_TEXT}
             iconSrc="/icons/floorplan.png"
             nodes={guides}
             noun="guide image"

packages/editor/src/index.tsx

@@ -65,6 +65,7 @@ export { useFreshPlacementVisibility } from './components/tools/shared/fresh-pla
 // Phase 5 Stage D — PolygonEditor for slab/ceiling boundary + hole editors.
 export {
   PolygonEditor,
+  type PolygonEditorPlanPointSnapContext,
   type PolygonEditorProps,
 } from './components/tools/shared/polygon-editor'
 export {
@@ -108,6 +109,7 @@ export {
   type WallDraftSnapKind,
   type WallDraftSnapResult,
   type WallPlanPoint,
+  type WallSnapRadii,
 } from './components/tools/wall/wall-drafting'
 // `ToolbarLeft` / `ToolbarRight` are the headless-spec aliases for the
 // existing `ViewerToolbarLeft` / `ViewerToolbarRight` exports — the
@@ -172,6 +174,13 @@ export { type UseDragActionArgs, useDragAction } from './hooks/use-drag-action'
 // Phase 5 Stage D — extras for kind-owned placement tools (FenceTool etc.).
 export { markToolCancelConsumed } from './hooks/use-keyboard'
 export { type Selection, useSelection } from './hooks/use-selection'
+export {
+  CEILING_ALIGNMENT_THRESHOLD_M,
+  type CeilingPlanSnapInput,
+  type CeilingPlanSnapResult,
+  clearCeilingSnapFeedback,
+  resolveCeilingPlanPointSnap,
+} from './lib/ceiling-plan-snap'
 export { EDITOR_LAYER } from './lib/constants'
 // Helper libs used by the kind-owned roof / stair / elevator panels.
 export {
@@ -230,9 +239,20 @@ export {
   resolvePlanarCursorPosition,
 } from './lib/planar-cursor-placement'
 export { clearRoofDuplicateMetadata, duplicateRoofSubtree } from './lib/roof-duplication'
+// Roof wall-face hit resolution + overlap guard — shared by the
+// kind-owned door / window tools in `@pascal-app/nodes` and the item
+// placement coordinator's roof-wall strategy.
+export { hasRoofFaceChildOverlap, type RoofWallHit, resolveRoofWallHit } from './lib/roof-wall-hit'
 export type { SceneGraph } from './lib/scene'
 export { applySceneGraphToEditor } from './lib/scene'
 export { triggerSFX } from './lib/sfx-bus'
+export {
+  clearSlabSnapFeedback,
+  resolveSlabPlanPointSnap,
+  SLAB_ALIGNMENT_THRESHOLD_M,
+  type SlabPlanSnapInput,
+  type SlabPlanSnapResult,
+} from './lib/slab-plan-snap'
 export { duplicateStairSubtree } from './lib/stair-duplication'
 export {
   getBuildingLevelsForLevel,
@@ -242,6 +262,13 @@ export {
   resolveStairPlacementLevelId,
   resolveStairToLevelId,
 } from './lib/stair-levels'
+export {
+  clearSurfacePlanSnapFeedback,
+  resolveSurfacePlanPointSnap,
+  SURFACE_ALIGNMENT_THRESHOLD_M,
+  type SurfacePlanSnapInput,
+  type SurfacePlanSnapResult,
+} from './lib/surface-plan-snap'
 // `cn` (twMerge + clsx) — used by kind-owned panels in `@pascal-app/
 // nodes` so they don't need their own copy / their own tailwind-merge
 // dependency.

packages/editor/src/lib/ceiling-plan-snap.ts

@@ -0,0 +1,24 @@
+import {
+  clearSurfacePlanSnapFeedback,
+  resolveSurfacePlanPointSnap,
+  SURFACE_ALIGNMENT_THRESHOLD_M,
+  type SurfacePlanSnapInput,
+  type SurfacePlanSnapResult,
+} from './surface-plan-snap'
+
+const CEILING_SNAP_MOVING_ID = '__ceiling_snap__'
+
+export const CEILING_ALIGNMENT_THRESHOLD_M = SURFACE_ALIGNMENT_THRESHOLD_M
+export type CeilingPlanSnapInput = SurfacePlanSnapInput
+export type CeilingPlanSnapResult = SurfacePlanSnapResult
+
+export function clearCeilingSnapFeedback() {
+  clearSurfacePlanSnapFeedback()
+}
+
+export function resolveCeilingPlanPointSnap(input: CeilingPlanSnapInput): CeilingPlanSnapResult {
+  return resolveSurfacePlanPointSnap({
+    ...input,
+    movingId: input.movingId ?? CEILING_SNAP_MOVING_ID,
+  })
+}

packages/editor/src/lib/roof-wall-hit.ts

@@ -0,0 +1,164 @@
+import {
+  type AnyNodeId,
+  getRoofSegmentWallFaces,
+  getScaledDimensions,
+  type ItemNode,
+  type RoofNode,
+  type RoofSegmentNode,
+  type RoofSegmentWallFace,
+  type RoofWallFaceId,
+  sceneRegistry,
+  segmentPointToRoofWallFace,
+  useScene,
+} from '@pascal-app/core'
+import * as THREE from 'three'
+
+const worldPoint = new THREE.Vector3()
+const worldNormal = new THREE.Vector3()
+const localPoint = new THREE.Vector3()
+const localNormal = new THREE.Vector3()
+const inverseMatrix = new THREE.Matrix4()
+
+export type RoofWallHit = {
+  segment: RoofSegmentNode
+  face: RoofSegmentWallFace
+  /** Face coords of the hit (u along the face, v above the segment base). */
+  u: number
+  v: number
+}
+
+/** Pointer hits more than this far off the wall plane are not wall hits. */
+const PLANE_TOLERANCE = 0.06
+/** Reject faces whose normal disagrees with the hit normal (slope / soffit). */
+const NORMAL_ALIGNMENT = 0.7
+/** A wall face is vertical; slope faces on low pitches have |ny| ≫ 0. */
+const MAX_NORMAL_Y = 0.4
+
+/**
+ * Resolve a pointer hit on a roof to one of its segments' vertical wall
+ * faces (base walls under the roof + the coplanar gable/shed/gambrel end
+ * faces). Counterpart of `resolveRoofSegmentHit`, which resolves to the
+ * sloped top surface instead.
+ *
+ * `normal` must be the raw `NodeEvent.normal` (hit-object-local) together
+ * with the `object` it came from — roof events can originate from the
+ * merged-roof mesh (roof-local frame) or a painted segment mesh
+ * (segment-local frame), so the normal is normalised through world space
+ * here instead of trusting the event frame.
+ *
+ * Lives in `@pascal-app/editor` because both the kind-owned door/window
+ * tools (in `@pascal-app/nodes`, which depends on editor) and the item
+ * placement coordinator (in editor itself) consume it.
+ */
+export function resolveRoofWallHit(
+  roof: RoofNode,
+  position: [number, number, number],
+  normal: [number, number, number] | undefined,
+  object: THREE.Object3D | undefined,
+): RoofWallHit | null {
+  if (!normal || !object) return null
+
+  worldPoint.set(position[0], position[1], position[2])
+  worldNormal.set(normal[0], normal[1], normal[2])
+  object.updateWorldMatrix(true, false)
+  worldNormal.transformDirection(object.matrixWorld)
+
+  const state = useScene.getState()
+  let best: { hit: RoofWallHit; score: number } | null = null
+
+  for (const childId of roof.children ?? []) {
+    const segment = state.nodes[childId as AnyNodeId] as RoofSegmentNode | undefined
+    if (segment?.type !== 'roof-segment') continue
+    const segObj = sceneRegistry.nodes.get(segment.id)
+    if (!segObj) continue
+    segObj.updateWorldMatrix(true, false)
+
+    localPoint.copy(worldPoint)
+    segObj.worldToLocal(localPoint)
+    inverseMatrix.copy(segObj.matrixWorld).invert()
+    localNormal.copy(worldNormal).transformDirection(inverseMatrix)
+
+    if (Math.abs(localNormal.y) > MAX_NORMAL_Y) continue
+
+    for (const face of getRoofSegmentWallFaces(segment)) {
+      const alignment =
+        localNormal.x * face.normal[0] +
+        localNormal.y * face.normal[1] +
+        localNormal.z * face.normal[2]
+      if (alignment < NORMAL_ALIGNMENT) continue
+
+      const { u, v, dist } = segmentPointToRoofWallFace(segment, face.id, [
+        localPoint.x,
+        localPoint.y,
+        localPoint.z,
+      ])
+      if (Math.abs(dist) > PLANE_TOLERANCE) continue
+      if (u < -PLANE_TOLERANCE || u > face.length + PLANE_TOLERANCE) continue
+      if (v < -PLANE_TOLERANCE) continue
+
+      const score = Math.abs(dist)
+      if (!best || score < best.score) {
+        best = { hit: { segment, face, u, v }, score }
+      }
+    }
+  }
+
+  return best?.hit ?? null
+}
+
+/**
+ * Overlap guard for nodes sharing a roof-segment wall face — the
+ * roof-host analogue of `hasWallChildOverlap`. Hosted children store
+ * FACE-LOCAL coords + an explicit `roofFace`, so siblings compare
+ * directly: doors/windows are center-anchored in v, wall items
+ * bottom-anchored.
+ */
+export function hasRoofFaceChildOverlap(
+  segment: RoofSegmentNode,
+  faceId: RoofWallFaceId,
+  u: number,
+  v: number,
+  width: number,
+  height: number,
+  ignoreId?: string,
+): boolean {
+  const nodes = useScene.getState().nodes
+  const newLeft = u - width / 2
+  const newRight = u + width / 2
+  const newBottom = v - height / 2
+  const newTop = v + height / 2
+
+  for (const childId of segment.children ?? []) {
+    if (childId === ignoreId) continue
+    const child = nodes[childId as AnyNodeId]
+    if (!child) continue
+    if ((child as { roofFace?: RoofWallFaceId }).roofFace !== faceId) continue
+    const position = (child as { position?: [number, number, number] }).position
+    if (!position) continue
+
+    let childW: number
+    let childBottom: number
+    let childTop: number
+    if (child.type === 'door' || child.type === 'window') {
+      const opening = child as { width: number; height: number }
+      childW = opening.width
+      childBottom = position[1] - opening.height / 2
+      childTop = position[1] + opening.height / 2
+    } else if (child.type === 'item') {
+      const item = child as ItemNode
+      if (item.asset.attachTo !== 'wall' && item.asset.attachTo !== 'wall-side') continue
+      const [w, h] = getScaledDimensions(item)
+      childW = w
+      // Items anchor position[1] at their bottom edge.
+      childBottom = position[1]
+      childTop = position[1] + h
+    } else {
+      continue
+    }
+
+    const xOverlap = newLeft < position[0] + childW / 2 && newRight > position[0] - childW / 2
+    const yOverlap = newBottom < childTop && newTop > childBottom
+    if (xOverlap && yOverlap) return true
+  }
+  return false
+}

packages/editor/src/lib/slab-plan-snap.ts

@@ -0,0 +1,25 @@
+import {
+  clearSurfacePlanSnapFeedback,
+  resolveSurfacePlanPointSnap,
+  SURFACE_ALIGNMENT_THRESHOLD_M,
+  type SurfacePlanSnapInput,
+  type SurfacePlanSnapResult,
+} from './surface-plan-snap'
+
+const SLAB_SNAP_MOVING_ID = '__slab_snap__'
+
+export const SLAB_ALIGNMENT_THRESHOLD_M = SURFACE_ALIGNMENT_THRESHOLD_M
+export type SlabPlanSnapInput = SurfacePlanSnapInput
+export type SlabPlanSnapResult = SurfacePlanSnapResult
+
+export function clearSlabSnapFeedback() {
+  clearSurfacePlanSnapFeedback()
+}
+
+export function resolveSlabPlanPointSnap(input: SlabPlanSnapInput): SlabPlanSnapResult {
+  return resolveSurfacePlanPointSnap({
+    ...input,
+    highlightWalls: input.highlightWalls ?? false,
+    movingId: input.movingId ?? SLAB_SNAP_MOVING_ID,
+  })
+}

packages/editor/src/lib/surface-plan-snap.ts

@@ -0,0 +1,239 @@
+import {
+  type AlignmentAnchor,
+  type AlignmentGuide,
+  type AnyNode,
+  collectAlignmentAnchors,
+  getWallCurveFrameAt,
+  getWallCurveLength,
+  isCurvedWall,
+  resolveAlignment,
+  resolveLevelId,
+  useScene,
+  type WallNode,
+} from '@pascal-app/core'
+import {
+  getSegmentGridStep,
+  snapWallDraftPointDetailed,
+  type WallDraftSnapKind,
+  type WallPlanPoint,
+  type WallSnapRadii,
+} from '../components/tools/wall/wall-drafting'
+import useAlignmentGuides from '../store/use-alignment-guides'
+import useEditor from '../store/use-editor'
+import useWallSnapIndicator from '../store/use-wall-snap-indicator'
+
+const SURFACE_SNAP_MOVING_ID = '__surface_snap__'
+export const SURFACE_ALIGNMENT_THRESHOLD_M = 0.08
+const SURFACE_WALL_SNAP_RADII = {
+  endpoint: 0.38,
+  midpoint: 0.28,
+  intersection: 0.28,
+  wall: 0.18,
+} satisfies WallSnapRadii
+const WALL_SOURCE_MATCH_EPSILON = 0.035
+
+export type SurfacePlanSnapInput = {
+  rawPoint: WallPlanPoint
+  fallbackPoint?: WallPlanPoint
+  levelId?: string | null
+  excludeId?: string | null
+  movingId?: string
+  nodes?: Readonly<Record<string, AnyNode>>
+  walls?: readonly WallNode[]
+  candidates?: readonly AlignmentAnchor[]
+  threshold?: number
+  altKey?: boolean
+  magnetic?: boolean
+  align?: boolean
+  highlightWalls?: boolean
+  step?: number
+  snapRadii?: WallSnapRadii
+}
+
+export type SurfacePlanSnapResult = {
+  point: WallPlanPoint
+  wallSnap: WallDraftSnapKind | null
+  guides: AlignmentGuide[]
+  wallIds: string[]
+}
+
+function getLevelWalls(
+  nodes: Readonly<Record<string, AnyNode>>,
+  levelId: string | null | undefined,
+  walls?: readonly WallNode[],
+): WallNode[] {
+  const source =
+    walls ?? Object.values(nodes).filter((node): node is WallNode => node.type === 'wall')
+  if (!levelId) return source.filter((wall) => wall.visible !== false)
+
+  return source.filter(
+    (wall) =>
+      wall.visible !== false && resolveLevelId(wall, nodes as Record<string, AnyNode>) === levelId,
+  )
+}
+
+function distanceSquared(a: WallPlanPoint, b: WallPlanPoint) {
+  const dx = a[0] - b[0]
+  const dz = a[1] - b[1]
+  return dx * dx + dz * dz
+}
+
+function wallMidpoint(wall: WallNode): WallPlanPoint {
+  if (isCurvedWall(wall)) {
+    const frame = getWallCurveFrameAt(wall, 0.5)
+    return [frame.point.x, frame.point.y]
+  }
+  return [(wall.start[0] + wall.end[0]) / 2, (wall.start[1] + wall.end[1]) / 2]
+}
+
+function distanceToSegmentSquared(point: WallPlanPoint, start: WallPlanPoint, end: WallPlanPoint) {
+  const dx = end[0] - start[0]
+  const dz = end[1] - start[1]
+  const lengthSquared = dx * dx + dz * dz
+  if (lengthSquared < 1e-9) return distanceSquared(point, start)
+
+  const t = Math.max(
+    0,
+    Math.min(1, ((point[0] - start[0]) * dx + (point[1] - start[1]) * dz) / lengthSquared),
+  )
+  const projected: WallPlanPoint = [start[0] + dx * t, start[1] + dz * t]
+  return distanceSquared(point, projected)
+}
+
+function distanceToWallSquared(point: WallPlanPoint, wall: WallNode) {
+  if (!isCurvedWall(wall)) {
+    return distanceToSegmentSquared(point, wall.start, wall.end)
+  }
+
+  const sampleCount = Math.max(8, Math.ceil(getWallCurveLength(wall) / 0.3))
+  let bestDistanceSquared = Number.POSITIVE_INFINITY
+  let previous = getWallCurveFrameAt(wall, 0).point
+  for (let index = 1; index <= sampleCount; index += 1) {
+    const current = getWallCurveFrameAt(wall, index / sampleCount).point
+    const distance = distanceToSegmentSquared(
+      point,
+      [previous.x, previous.y],
+      [current.x, current.y],
+    )
+    bestDistanceSquared = Math.min(bestDistanceSquared, distance)
+    previous = current
+  }
+  return bestDistanceSquared
+}
+
+function closestWallIds(point: WallPlanPoint, walls: readonly WallNode[], count: number) {
+  return walls
+    .map((wall) => ({ id: wall.id, distance: distanceToWallSquared(point, wall) }))
+    .sort((a, b) => a.distance - b.distance)
+    .slice(0, count)
+    .map(({ id }) => id)
+}
+
+function findSnapSourceWallIds(
+  point: WallPlanPoint,
+  kind: WallDraftSnapKind,
+  walls: readonly WallNode[],
+): string[] {
+  const epsilonSquared = WALL_SOURCE_MATCH_EPSILON ** 2
+
+  if (kind === 'endpoint') {
+    const endpointMatches = walls.filter(
+      (wall) =>
+        distanceSquared(point, wall.start) <= epsilonSquared ||
+        distanceSquared(point, wall.end) <= epsilonSquared,
+    )
+    if (endpointMatches.length > 0) return endpointMatches.map((wall) => wall.id)
+    return closestWallIds(point, walls, 1)
+  }
+
+  if (kind === 'midpoint') {
+    const midpointMatches = walls.filter(
+      (wall) => distanceSquared(point, wallMidpoint(wall)) <= epsilonSquared,
+    )
+    if (midpointMatches.length > 0) return midpointMatches.map((wall) => wall.id)
+    return closestWallIds(point, walls, 1)
+  }
+
+  if (kind === 'intersection') {
+    const crossingMatches = walls.filter(
+      (wall) => distanceToWallSquared(point, wall) <= epsilonSquared,
+    )
+    if (crossingMatches.length > 0) return crossingMatches.map((wall) => wall.id).slice(0, 2)
+    return closestWallIds(point, walls, 2)
+  }
+
+  return closestWallIds(point, walls, 1)
+}
+
+export function clearSurfacePlanSnapFeedback() {
+  useAlignmentGuides.getState().clear()
+  useWallSnapIndicator.getState().clear()
+}
+
+export function resolveSurfacePlanPointSnap(input: SurfacePlanSnapInput): SurfacePlanSnapResult {
+  const nodes = input.nodes ?? useScene.getState().nodes
+  const walls = getLevelWalls(nodes, input.levelId, input.walls)
+  const fallbackPoint = input.fallbackPoint
+  const magnetic = input.magnetic ?? useEditor.getState().magneticSnap
+
+  const wallSnap = snapWallDraftPointDetailed({
+    point: input.rawPoint,
+    walls,
+    step: input.step ?? getSegmentGridStep(),
+    magnetic,
+    snapRadii: input.snapRadii ?? SURFACE_WALL_SNAP_RADII,
+    gridSnap: fallbackPoint ? () => fallbackPoint : undefined,
+  })
+
+  if (wallSnap.snap) {
+    const wallIds =
+      input.highlightWalls === false
+        ? []
+        : findSnapSourceWallIds(wallSnap.point, wallSnap.snap, walls)
+    useWallSnapIndicator.getState().set({
+      x: wallSnap.point[0],
+      z: wallSnap.point[1],
+      kind: wallSnap.snap,
+      ...(wallIds.length > 0 ? { wallIds } : {}),
+    })
+    useAlignmentGuides.getState().clear()
+    return { point: wallSnap.point, wallSnap: wallSnap.snap, guides: [], wallIds }
+  }
+
+  useWallSnapIndicator.getState().clear()
+
+  const basePoint = fallbackPoint ?? wallSnap.point
+  if (input.align === false || input.altKey) {
+    useAlignmentGuides.getState().clear()
+    return { point: basePoint, wallSnap: null, guides: [], wallIds: [] }
+  }
+
+  const movingId = input.movingId ?? SURFACE_SNAP_MOVING_ID
+  const candidates =
+    input.candidates ??
+    collectAlignmentAnchors(nodes, input.excludeId ?? movingId, input.levelId ?? null)
+
+  if (candidates.length === 0) {
+    useAlignmentGuides.getState().clear()
+    return { point: basePoint, wallSnap: null, guides: [], wallIds: [] }
+  }
+
+  const alignment = resolveAlignment({
+    moving: [{ nodeId: movingId, kind: 'corner', x: basePoint[0], z: basePoint[1] }],
+    candidates,
+    threshold: input.threshold ?? SURFACE_ALIGNMENT_THRESHOLD_M,
+  })
+
+  useAlignmentGuides.getState().set(alignment.guides)
+
+  if (!alignment.snap) {
+    return { point: basePoint, wallSnap: null, guides: alignment.guides, wallIds: [] }
+  }
+
+  return {
+    point: [basePoint[0] + alignment.snap.dx, basePoint[1] + alignment.snap.dz],
+    wallSnap: null,
+    guides: alignment.guides,
+    wallIds: [],
+  }
+}

packages/editor/src/store/use-wall-snap-indicator.ts

@@ -15,6 +15,8 @@ export type WallSnapPoint = {
   x: number
   z: number
   kind: WallSnapKind
+  /** Optional wall ids whose geometry produced this snap. */
+  wallIds?: string[]
 }
 
 type WallSnapIndicatorState = {

packages/nodes/src/ceiling/boundary-editor.tsx

@@ -1,9 +1,15 @@
 'use client'
 
 import { type CeilingNode, resolveLevelId, useLiveNodeOverrides, useScene } from '@pascal-app/core'
-import { PolygonEditor } from '@pascal-app/editor'
+import {
+  clearCeilingSnapFeedback,
+  PolygonEditor,
+  type PolygonEditorPlanPointSnapContext,
+  resolveCeilingPlanPointSnap,
+  triggerSFX,
+} from '@pascal-app/editor'
 import { useViewer } from '@pascal-app/viewer'
-import { useCallback, useEffect } from 'react'
+import { useCallback, useEffect, useMemo, useRef } from 'react'
 
 /**
  * Phase 5 Stage D — ceiling boundary editor (registry-driven).
@@ -23,11 +29,26 @@ export const CeilingBoundaryEditor: React.FC<{ ceilingId: CeilingNode['id'] }> =
   const updateNode = useScene((s) => s.updateNode)
   const markDirty = useScene((s) => s.markDirty)
   const setSelection = useViewer((s) => s.setSelection)
+  const setHoveredId = useViewer((s) => s.setHoveredId)
+  const ownsCeilingHoverRef = useRef(false)
+  const ownsPolygonPreviewRef = useRef(false)
+  const liveOverride = useLiveNodeOverrides((state) => {
+    if (ownsPolygonPreviewRef.current) return null
+    return state.overrides.get(ceilingId) as Partial<CeilingNode> | undefined
+  })
 
   const ceiling = ceilingNode?.type === 'ceiling' ? (ceilingNode as CeilingNode) : null
+  const effectiveCeiling = useMemo(
+    () => (ceiling && liveOverride ? ({ ...ceiling, ...liveOverride } as CeilingNode) : ceiling),
+    [ceiling, liveOverride],
+  )
+  const ceilingLevelId = effectiveCeiling
+    ? resolveLevelId(effectiveCeiling, useScene.getState().nodes)
+    : null
 
   const handlePolygonChange = useCallback(
     (newPolygon: Array<[number, number]>) => {
+      clearCeilingSnapFeedback()
       updateNode(ceilingId, { polygon: newPolygon })
       setSelection({ selectedIds: [ceilingId] })
     },
@@ -37,36 +58,112 @@ export const CeilingBoundaryEditor: React.FC<{ ceilingId: CeilingNode['id'] }> =
   const handlePolygonPreview = useCallback(
     (preview: ReadonlyArray<readonly [number, number]> | null) => {
       if (preview) {
+        ownsPolygonPreviewRef.current = true
         useLiveNodeOverrides.getState().set(ceilingId, {
           polygon: preview.map(([x, z]) => [x, z] as [number, number]),
         })
       } else {
         useLiveNodeOverrides.getState().clear(ceilingId)
+        ownsPolygonPreviewRef.current = false
       }
       markDirty(ceilingId)
     },
     [ceilingId, markDirty],
   )
 
+  const setCeilingHandleHover = useCallback(
+    (active: boolean) => {
+      if (active) {
+        ownsCeilingHoverRef.current = true
+        setHoveredId(ceilingId)
+        return
+      }
+      if (ownsCeilingHoverRef.current && useViewer.getState().hoveredId === ceilingId) {
+        setHoveredId(null)
+      }
+      ownsCeilingHoverRef.current = false
+    },
+    [ceilingId, setHoveredId],
+  )
+
+  const handleHandleHoverChange = useCallback(
+    (index: number | null) => {
+      setCeilingHandleHover(index !== null)
+    },
+    [setCeilingHandleHover],
+  )
+
+  const handleDragStateChange = useCallback(
+    (isDragging: boolean) => {
+      if (!isDragging) {
+        ownsPolygonPreviewRef.current = false
+        clearCeilingSnapFeedback()
+      }
+      setCeilingHandleHover(isDragging)
+    },
+    [setCeilingHandleHover],
+  )
+
+  const handlePolygonEditorDragCommit = useCallback(() => {
+    triggerSFX('sfx:item-place')
+    clearCeilingSnapFeedback()
+  }, [])
+
+  const handlePolygonEditorDragStart = useCallback(() => {
+    ownsPolygonPreviewRef.current = true
+    triggerSFX('sfx:item-pick')
+  }, [])
+
+  const handlePolygonEditorBeforeVertexDrag = useCallback(() => {
+    ownsPolygonPreviewRef.current = true
+  }, [])
+
+  const resolvePolygonEditorPlanPoint = useCallback(
+    (context: PolygonEditorPlanPointSnapContext) =>
+      resolveCeilingPlanPointSnap({
+        rawPoint: context.rawPoint,
+        fallbackPoint: context.gridPoint,
+        levelId: ceilingLevelId,
+        excludeId: ceilingId,
+        altKey: context.nativeEvent?.altKey === true,
+      }).point,
+    [ceilingId, ceilingLevelId],
+  )
+
   useEffect(() => {
     return () => {
+      clearCeilingSnapFeedback()
       useLiveNodeOverrides.getState().clear(ceilingId)
       useScene.getState().markDirty(ceilingId)
+      ownsPolygonPreviewRef.current = false
+      if (ownsCeilingHoverRef.current && useViewer.getState().hoveredId === ceilingId) {
+        useViewer.getState().setHoveredId(null)
+      }
+      ownsCeilingHoverRef.current = false
     }
   }, [ceilingId])
 
-  if (!ceiling?.polygon || ceiling.polygon.length < 3) return null
+  if (!effectiveCeiling?.polygon || effectiveCeiling.polygon.length < 3) return null
 
   return (
     <PolygonEditor
       allowEdgeMove
       color="#d4d4d4"
-      levelId={resolveLevelId(ceiling, useScene.getState().nodes)}
+      highlightConnectedHandles
+      levelId={ceilingLevelId ?? undefined}
       minVertices={3}
+      onBeforeVertexDrag={handlePolygonEditorBeforeVertexDrag}
+      onDragCommit={handlePolygonEditorDragCommit}
+      onDragStart={handlePolygonEditorDragStart}
+      onDragStateChange={handleDragStateChange}
+      onEdgeHoverChange={handleHandleHoverChange}
+      onMidpointHoverChange={handleHandleHoverChange}
       onPolygonChange={handlePolygonChange}
       onPolygonPreview={handlePolygonPreview}
-      polygon={ceiling.polygon}
-      surfaceHeight={ceiling.height ?? 2.5}
+      onVertexHoverChange={handleHandleHoverChange}
+      polygon={effectiveCeiling.polygon}
+      resolvePlanPoint={resolvePolygonEditorPlanPoint}
+      surfaceHeight={effectiveCeiling.height ?? 2.5}
     />
   )
 }

packages/nodes/src/ceiling/floorplan-affordances.ts

@@ -1,8 +1,10 @@
-import type { CeilingNode } from '@pascal-app/core'
+import { type AnyNode, type CeilingNode, resolveLevelId } from '@pascal-app/core'
+import { resolveCeilingPlanPointSnap } from '@pascal-app/editor'
 import {
   createPolygonAddVertexAffordance,
   createPolygonMoveEdgeAffordance,
   createPolygonVertexAffordance,
+  type PolygonAffordanceSnapContext,
 } from '../shared/polygon-vertex-affordance'
 
 /**
@@ -11,6 +13,35 @@ import {
  * optional `holeIndex`. See `slab/floorplan-affordances.ts` for the
  * full contract.
  */
-export const ceilingMoveVertexAffordance = createPolygonVertexAffordance<CeilingNode>('ceiling')
-export const ceilingAddVertexAffordance = createPolygonAddVertexAffordance<CeilingNode>('ceiling')
-export const ceilingMoveEdgeAffordance = createPolygonMoveEdgeAffordance<CeilingNode>('ceiling')
+const ceilingSnapOptions = {
+  resolvePlanPoint({
+    node,
+    nodes,
+    rawPoint,
+    fallbackPoint,
+    modifiers,
+  }: PolygonAffordanceSnapContext<CeilingNode>) {
+    const sceneNodes = nodes as Record<string, AnyNode>
+    return resolveCeilingPlanPointSnap({
+      rawPoint,
+      fallbackPoint,
+      levelId: resolveLevelId(node, sceneNodes),
+      excludeId: node.id,
+      nodes: sceneNodes,
+      altKey: modifiers.altKey,
+    }).point
+  },
+}
+
+export const ceilingMoveVertexAffordance = createPolygonVertexAffordance<CeilingNode>(
+  'ceiling',
+  ceilingSnapOptions,
+)
+export const ceilingAddVertexAffordance = createPolygonAddVertexAffordance<CeilingNode>(
+  'ceiling',
+  ceilingSnapOptions,
+)
+export const ceilingMoveEdgeAffordance = createPolygonMoveEdgeAffordance<CeilingNode>(
+  'ceiling',
+  ceilingSnapOptions,
+)

packages/nodes/src/ceiling/tool.tsx

@@ -1,19 +1,13 @@
 'use client'
 
-import {
-  collectAlignmentAnchors,
-  emitter,
-  type GridEvent,
-  type LevelNode,
-  resolveAlignment,
-  useScene,
-} from '@pascal-app/core'
+import { emitter, type GridEvent, type LevelNode, useScene } from '@pascal-app/core'
 import {
   CursorSphere,
+  clearCeilingSnapFeedback,
   EDITOR_LAYER,
   markToolCancelConsumed,
+  resolveCeilingPlanPointSnap,
   triggerSFX,
-  useAlignmentGuides,
   useEditor,
 } from '@pascal-app/editor'
 import { useViewer } from '@pascal-app/viewer'
@@ -33,8 +27,6 @@ import { CeilingNode } from './schema'
 
 const CEILING_HEIGHT = 2.52
 const GRID_OFFSET = 0.02
-/** Figma-style alignment-snap threshold (meters), matching the move tools. */
-const ALIGNMENT_THRESHOLD_M = 0.08
 
 function calculateSnapPoint(
   lastPoint: [number, number],
@@ -93,10 +85,7 @@ export const CeilingTool: React.FC = () => {
   // draw isn't built with a stale preset's parameters. Unmount-only.
   useEffect(() => () => useEditor.getState().setToolDefaults('ceiling', null), [])
 
-  // Clear alignment guides on unmount ONLY. The main drawing effect re-runs
-  // on every cursor move (cursorPosition is in its deps), so clearing guides
-  // in its cleanup would wipe the guide the instant after each move sets it.
-  useEffect(() => () => useAlignmentGuides.getState().clear(), [])
+  useEffect(() => () => clearCeilingSnapFeedback(), [])
 
   const verticalGeo = useMemo(
     () =>
@@ -115,44 +104,6 @@ export const CeilingTool: React.FC = () => {
   useEffect(() => {
     if (!currentLevelId) return
 
-    // Alignment candidates — anchors of every OTHER alignable object. The
-    // ceiling's own in-progress vertices are intentionally excluded (no
-    // self-alignment while drawing).
-    const alignmentCandidates = collectAlignmentAnchors(useScene.getState().nodes, '')
-    // Snap the drafted vertex onto another object's nearest real anchor and
-    // publish the guide. The probe is the RAW cursor, NOT the 0.5m-grid-snapped
-    // point: resolving against the grid point would only ever catch anchors
-    // that happen to sit on a grid line, so off-grid items (furniture, angled
-    // walls) would never surface a guide. The matched axis locks exactly to the
-    // candidate's coordinate; the other axis keeps its grid/ortho snap. Alt
-    // bypasses.
-    const alignPoint = (
-      fallback: [number, number],
-      raw: [number, number],
-      bypass: boolean,
-    ): [number, number] => {
-      if (bypass || alignmentCandidates.length === 0) {
-        useAlignmentGuides.getState().clear()
-        return fallback
-      }
-      const ar = resolveAlignment({
-        moving: [{ nodeId: '__ceiling-draft__', kind: 'corner', x: raw[0], z: raw[1] }],
-        candidates: alignmentCandidates,
-        threshold: ALIGNMENT_THRESHOLD_M,
-      })
-      if (ar.guides.length === 0) {
-        useAlignmentGuides.getState().clear()
-        return fallback
-      }
-      useAlignmentGuides.getState().set(ar.guides)
-      let [x, z] = fallback
-      for (const guide of ar.guides) {
-        if (guide.axis === 'x') x = guide.coord
-        else z = guide.coord
-      }
-      return [x, z]
-    }
-
     const onGridMove = (event: GridEvent) => {
       if (!(cursorRef.current && gridCursorRef.current)) return
       const rawPoint: [number, number] = [event.localPosition[0], event.localPosition[2]]
@@ -168,7 +119,12 @@ export const CeilingTool: React.FC = () => {
         shiftPressed.current || !lastPoint
           ? gridPosition
           : calculateSnapPoint(lastPoint, gridPosition)
-      const displayPoint = alignPoint(orthoPoint, rawPoint, event.nativeEvent?.altKey === true)
+      const displayPoint = resolveCeilingPlanPointSnap({
+        rawPoint,
+        fallbackPoint: orthoPoint,
+        levelId: currentLevelId,
+        altKey: event.nativeEvent?.altKey === true,
+      }).point
       setSnappedCursorPosition(displayPoint)
       if (
         points.length > 0 &&
@@ -199,7 +155,7 @@ export const CeilingTool: React.FC = () => {
         const ceilingId = commitCeilingDrawing(currentLevelId, points)
         setSelection({ selectedIds: [ceilingId] })
         setPoints([])
-        useAlignmentGuides.getState().clear()
+        clearCeilingSnapFeedback()
       } else {
         // Every non-closing vertex is a "start" tick; the closing click above
         // fires the structure-build (end) cue.
@@ -214,14 +170,14 @@ export const CeilingTool: React.FC = () => {
         const ceilingId = commitCeilingDrawing(currentLevelId, points)
         setSelection({ selectedIds: [ceilingId] })
         setPoints([])
-        useAlignmentGuides.getState().clear()
+        clearCeilingSnapFeedback()
       }
     }
 
     const onCancel = () => {
       if (points.length > 0) markToolCancelConsumed()
       setPoints([])
-      useAlignmentGuides.getState().clear()
+      clearCeilingSnapFeedback()
     }
 
     const onKeyDown = (e: KeyboardEvent) => {

packages/nodes/src/door/definition.ts

@@ -3,8 +3,11 @@ import type {
   DoorNode as DoorNodeType,
   HandleDescriptor,
   NodeDefinition,
+  RoofSegmentNode,
   WallNode,
 } from '@pascal-app/core'
+import { readRoofFaceHeightMax, readRoofFaceWidthMax } from '../shared/roof-opening-host'
+import { buildRoofWallOpeningCut } from '../shared/roof-wall-opening-cut'
 import { scaleHandleHeight } from './door-math'
 import { buildDoorFloorplan } from './floorplan'
 import { doorWidthAffordance } from './floorplan-affordances'
@@ -42,7 +45,13 @@ function doorWidthHandle(side: 'left' | 'right'): HandleDescriptor<DoorNodeType>
     // 'max' = +X edge anchored (left arrow grows the -X edge outward).
     anchor: side === 'right' ? 'min' : 'max',
     min: MIN_DOOR_WIDTH,
-    max: (n, scene) => readWallLength(n, scene),
+    max: (n, scene) => {
+      // Roof-hosted doors clamp against the face profile (the wall-based
+      // limits read Infinity when wallId is unset).
+      const roofMax = readRoofFaceWidthMax(n, scene, sign)
+      if (roofMax !== null) return Math.max(MIN_DOOR_WIDTH, roofMax)
+      return readWallLength(n, scene)
+    },
     currentValue: (n) => n.width,
     apply: (initial, newWidth) => {
       // Anchored edge stays fixed in wall-local coords. Door rotation is
@@ -80,6 +89,8 @@ function doorHeightHandle(): HandleDescriptor<DoorNodeType> {
     anchor: 'min', // bottom anchored at wall-local Y = position[1] - height/2
     min: MIN_DOOR_HEIGHT,
     max: (n, scene) => {
+      const roofMax = readRoofFaceHeightMax(n, scene, 1)
+      if (roofMax !== null) return Math.max(MIN_DOOR_HEIGHT, roofMax)
       const bottom = n.position[1] - n.height / 2
       return Math.max(MIN_DOOR_HEIGHT, readWallHeight(n, scene) - bottom)
     },
@@ -147,10 +158,22 @@ export const doorDefinition: NodeDefinition<typeof DoorNode> = {
     duplicable: true,
     deletable: true,
     wallOpeningPlacement: true,
-    // `wallId` ties the door to its host wall and is re-derived from
-    // the wall under the cursor when a preset is placed. Host apps
-    // strip this at preset-save time via `getHostRefFields(def)`.
-    hostRefFields: ['wallId'],
+    // Doors also host on roof-segment wall faces (base walls under the
+    // roof, gable ends). `buildCut` punches the opening into the
+    // segment's wall brush; `dirtyHandledByOwnSystem` keeps the roof-merge
+    // loop from consuming door dirty marks (DoorSystem owns them and
+    // already cascades to the host via parentId).
+    roofAccessory: {
+      buildCut: (node, hostSegment) =>
+        buildRoofWallOpeningCut(node as DoorNodeType, hostSegment as RoofSegmentNode),
+      cutScope: 'wall',
+      dirtyHandledByOwnSystem: true,
+    },
+    // `wallId` / `roofSegmentId` tie the door to its host and are
+    // re-derived from the surface under the cursor when a preset is
+    // placed. Host apps strip these at preset-save time via
+    // `getHostRefFields(def)`.
+    hostRefFields: ['wallId', 'roofSegmentId', 'roofFace'],
   },
 
   parametrics: doorParametrics,

packages/nodes/src/door/floorplan-move.ts

@@ -8,6 +8,10 @@ import {
 } from '@pascal-app/core'
 import { snapToHalf } from '@pascal-app/editor'
 import { createFloorplanCursorResolver } from '../shared/floorplan-cursor'
+import {
+  getRoofHostedOpeningLevelId,
+  getRoofHostedOpeningPlanPoint,
+} from '../shared/roof-opening-host'
 import {
   findClosestWallInPlan,
   projectWallLocalPointToPlan,
@@ -35,11 +39,13 @@ export const doorFloorplanMoveTarget: FloorplanMoveTarget<DoorNode> = ({ node })
   // Snapshot of the door's "valid" state at move-start — used by
   // canCommit to decide whether the current snapped position is OK.
   const startLevelId = (() => {
-    // Walk up via parentId until we hit a node whose type isn't 'wall'
-    // — that's the level (or null). The door is wall-hosted, so the
-    // wall's parent is the level. Cached at start because the parent
-    // chain doesn't change during a move.
-    const wall = useScene.getState().nodes[node.parentId as AnyNodeId]
+    // Wall-hosted: the wall's parent is the level. Roof-hosted: walk
+    // segment → roof → level. Cached at start because the parent chain
+    // doesn't change during a move.
+    const nodes = useScene.getState().nodes
+    const roofLevelId = getRoofHostedOpeningLevelId(node, nodes)
+    if (roofLevelId) return roofLevelId
+    const wall = nodes[node.parentId as AnyNodeId]
     return wall ? (wall.parentId as AnyNodeId | null) : null
   })()
   const originalWall = node.parentId
@@ -49,7 +55,7 @@ export const doorFloorplanMoveTarget: FloorplanMoveTarget<DoorNode> = ({ node })
     original:
       originalWall?.type === 'wall'
         ? projectWallLocalPointToPlan(originalWall, node.position[0])
-        : [node.position[0], 0],
+        : (getRoofHostedOpeningPlanPoint(node, useScene.getState().nodes) ?? [node.position[0], 0]),
     metadata: node.metadata,
   })
 
@@ -62,6 +68,8 @@ export const doorFloorplanMoveTarget: FloorplanMoveTarget<DoorNode> = ({ node })
     side: DoorNode['side']
     parentId: string
     wallId: string
+    roofSegmentId: undefined
+    roofFace: undefined
   } | null = null
 
   const session: FloorplanMoveTargetSession = {
@@ -94,6 +102,10 @@ export const doorFloorplanMoveTarget: FloorplanMoveTarget<DoorNode> = ({ node })
         side: hit.side,
         parentId: hit.wall.id,
         wallId: hit.wall.id,
+        // Re-anchoring to a wall ends any roof-segment hosting; the
+        // overlay's snapshot restores it if the move is reverted.
+        roofSegmentId: undefined,
+        roofFace: undefined,
       }
 
       // Build the updates atomically — position + rotation + side +

packages/nodes/src/door/move-tool.tsx

@@ -4,6 +4,8 @@ import {
   DoorNode,
   emitter,
   isCurvedWall,
+  type RoofEvent,
+  type RoofNode,
   sceneRegistry,
   spatialGridManager,
   useLiveTransforms,
@@ -25,6 +27,11 @@ import { useViewer } from '@pascal-app/viewer'
 import { useCallback, useEffect, useMemo, useRef } from 'react'
 import { BoxGeometry, EdgesGeometry, type Group } from 'three'
 import { LineBasicNodeMaterial } from 'three/webgpu'
+import {
+  getRoofWallOpeningCursorPose,
+  type RoofWallOpeningTarget,
+  resolveRoofWallOpeningTarget,
+} from '../shared/roof-wall-opening-placement'
 import { resolveWallSlideAlignment } from '../shared/wall-opening-alignment'
 import { clampToWall, hasWallChildOverlap, wallLocalToWorld } from './door-math'
 
@@ -57,6 +64,11 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
       side: movingDoorNode.side,
       parentId: movingDoorNode.parentId,
       wallId: movingDoorNode.wallId,
+      // Doors can be hosted on a roof-segment wall face. Moving onto a
+      // wall re-anchors as wall-hosted (roofSegmentId cleared); reverts
+      // must restore the roof host.
+      roofSegmentId: movingDoorNode.roofSegmentId,
+      roofFace: movingDoorNode.roofFace,
       metadata: movingDoorNode.metadata,
     }
 
@@ -66,7 +78,7 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
       })
     }
 
-    let currentWallId: string | null = movingDoorNode.parentId
+    let currentHostId: string | null = movingDoorNode.parentId
     let dragAnchor: { wallId: string; rawX: number; startX: number } | null = null
     let lastTarget: {
       wallNode: WallEvent['node']
@@ -80,18 +92,18 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
       event: WallEvent
     } | null = null
 
-    const markWallDirty = (wallId: string | null) => {
-      if (wallId) useScene.getState().dirtyNodes.add(wallId as AnyNodeId)
+    const markHostDirty = (hostId: string | null) => {
+      if (hostId) useScene.getState().dirtyNodes.add(hostId as AnyNodeId)
     }
-    const lastWallDirtyAt = new Map<string, number>()
-    const markWallDirtyThrottled = (wallId: string | null) => {
-      if (!wallId) return
+    const lastHostDirtyAt = new Map<string, number>()
+    const markHostDirtyThrottled = (hostId: string | null) => {
+      if (!hostId) return
       const now = globalThis.performance?.now?.() ?? Date.now()
-      const last = lastWallDirtyAt.get(wallId) ?? 0
+      const last = lastHostDirtyAt.get(hostId) ?? 0
       // Wall rebuilds can trigger expensive CSG; throttle live previews to avoid FPS collapse.
       if (now - last > 120) {
-        lastWallDirtyAt.set(wallId, now)
-        markWallDirty(wallId)
+        lastHostDirtyAt.set(hostId, now)
+        markHostDirty(hostId)
       }
     }
 
@@ -200,16 +212,18 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
     }
 
     const applyPreview = (target: NonNullable<typeof lastTarget>) => {
-      if (currentWallId !== target.wallId) {
+      if (currentHostId !== target.wallId) {
         useScene.getState().updateNode(movingDoorNode.id, {
           position: [target.clampedX, target.clampedY, 0],
           rotation: [0, target.itemRotation, 0],
           side: target.side,
           parentId: target.wallId,
           wallId: target.wallId,
+          roofSegmentId: undefined,
+          roofFace: undefined,
         })
-        markWallDirty(currentWallId)
-        currentWallId = target.wallId
+        markHostDirty(currentHostId)
+        currentHostId = target.wallId
       } else {
         const doorMesh = sceneRegistry.nodes.get(movingDoorNode.id as AnyNodeId)
         if (doorMesh) {
@@ -222,7 +236,7 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
         position: [target.clampedX, target.clampedY, 0],
         rotation: target.itemRotation,
       })
-      markWallDirtyThrottled(target.wallId)
+      markHostDirtyThrottled(target.wallId)
 
       updateCursor(
         wallLocalToWorld(
@@ -284,6 +298,8 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
           side: target.side,
           wallId: target.wallId,
           parentId: target.wallId,
+          roofSegmentId: undefined,
+          roofFace: undefined,
         })
         useScene.getState().createNode(node, target.wallId as AnyNodeId)
         placedId = node.id
@@ -294,6 +310,8 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
           side: original.side,
           parentId: original.parentId,
           wallId: original.wallId,
+          roofSegmentId: original.roofSegmentId,
+          roofFace: original.roofFace,
           metadata: original.metadata,
         })
         useScene.temporal.getState().resume()
@@ -304,16 +322,17 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
           side: target.side,
           parentId: target.wallId,
           wallId: target.wallId,
+          roofSegmentId: undefined,
           metadata: {},
         })
 
         if (original.parentId && original.parentId !== target.wallId) {
-          markWallDirty(original.parentId)
+          markHostDirty(original.parentId)
         }
         placedId = movingDoorNode.id
       }
 
-      markWallDirty(target.wallId)
+      markHostDirty(target.wallId)
       useLiveTransforms.getState().clear(movingDoorNode.id)
       useScene.temporal.getState().pause()
 
@@ -330,25 +349,97 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
       dragAnchor = null
       lastTarget = null
       if (isNew) return
-      if (currentWallId && currentWallId !== original.parentId) {
-        markWallDirty(currentWallId)
+      if (currentHostId && currentHostId !== original.parentId) {
+        markHostDirty(currentHostId)
       }
-      currentWallId = original.parentId
+      currentHostId = original.parentId
       useScene.getState().updateNode(movingDoorNode.id, {
         position: original.position,
         rotation: original.rotation,
         side: original.side,
         parentId: original.parentId,
         wallId: original.wallId,
+        roofSegmentId: original.roofSegmentId,
+        roofFace: original.roofFace,
       })
-      if (original.parentId) markWallDirty(original.parentId)
+      if (original.parentId) markHostDirty(original.parentId)
     }
 
-    const onCancel = () => {
+    // ── Roof-segment wall faces ─────────────────────────────────────
+    // Mirrors the wall flow for the segments' vertical wall faces (base
+    // walls under the roof + coplanar gable ends). This is also the
+    // placement path preset tiles take (`metadata.isNew` clones).
+
+    const resolveRoofMoveTarget = (event: RoofEvent) =>
+      resolveRoofWallOpeningTarget({
+        event,
+        width: movingDoorNode.width,
+        height: movingDoorNode.height,
+        ignoreId: movingDoorNode.id,
+        vertical: { kind: 'bottom-locked' },
+      })
+
+    const updateRoofCursor = (target: RoofWallOpeningTarget, roof: RoofNode) => {
+      const pose = getRoofWallOpeningCursorPose(target, roof)
+      if (pose) updateCursor(pose.position, pose.rotationY, target.valid)
+    }
+
+    const onRoofHover = (event: RoofEvent) => {
+      const target = resolveRoofMoveTarget(event)
+      if (!target) return
+      // Wall-frame drag anchor / live transform don't apply on a roof face.
+      dragAnchor = null
+      lastTarget = null
       useLiveTransforms.getState().clear(movingDoorNode.id)
+      if (currentHostId !== target.segment.id) {
+        useScene.getState().updateNode(movingDoorNode.id, {
+          position: target.position,
+          rotation: [0, 0, 0],
+          side: 'front',
+          parentId: target.segment.id,
+          wallId: undefined,
+          roofSegmentId: target.segment.id,
+          roofFace: target.face.id,
+        })
+        markHostDirty(currentHostId)
+        currentHostId = target.segment.id
+      } else {
+        useScene.getState().updateNode(movingDoorNode.id, {
+          position: target.position,
+          rotation: [0, 0, 0],
+          roofFace: target.face.id,
+        })
+      }
+      updateRoofCursor(target, event.node as RoofNode)
+      event.stopPropagation()
+    }
+
+    const onRoofClick = (event: RoofEvent) => {
+      const target = resolveRoofMoveTarget(event)
+      if (!target?.valid) return
+      const segmentId = target.segment.id
+
+      let placedId: string
+
       if (isNew) {
         useScene.getState().deleteNode(movingDoorNode.id)
-        if (currentWallId) markWallDirty(currentWallId)
+        useScene.temporal.getState().resume()
+
+        const cloned = structuredClone(movingDoorNode) as any
+        delete cloned.id
+        cloned.metadata = stripPlacementMetadataFlags(cloned.metadata)
+        const node = DoorNode.parse({
+          ...cloned,
+          position: target.position,
+          rotation: [0, 0, 0],
+          side: 'front',
+          wallId: undefined,
+          roofSegmentId: segmentId,
+          roofFace: target.face.id,
+          parentId: segmentId,
+        })
+        useScene.getState().createNode(node, segmentId as AnyNodeId)
+        placedId = node.id
       } else {
         useScene.getState().updateNode(movingDoorNode.id, {
           position: original.position,
@@ -356,9 +447,79 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
           side: original.side,
           parentId: original.parentId,
           wallId: original.wallId,
+          roofSegmentId: original.roofSegmentId,
+          roofFace: original.roofFace,
           metadata: original.metadata,
         })
-        if (original.parentId) markWallDirty(original.parentId)
+        useScene.temporal.getState().resume()
+
+        useScene.getState().updateNode(movingDoorNode.id, {
+          position: target.position,
+          rotation: [0, 0, 0],
+          side: 'front',
+          parentId: segmentId,
+          wallId: undefined,
+          roofSegmentId: segmentId,
+          roofFace: target.face.id,
+          metadata: {},
+        })
+
+        if (original.parentId && original.parentId !== segmentId) {
+          markHostDirty(original.parentId)
+        }
+        placedId = movingDoorNode.id
+      }
+
+      markHostDirty(segmentId)
+      useLiveTransforms.getState().clear(movingDoorNode.id)
+      useScene.temporal.getState().pause()
+
+      triggerSFX('sfx:structure-build')
+      hideCursor()
+      useViewer.getState().setSelection({ selectedIds: [placedId] })
+      exitMoveMode()
+      event.stopPropagation()
+    }
+
+    const onRoofLeave = () => {
+      hideCursor()
+      useLiveTransforms.getState().clear(movingDoorNode.id)
+      dragAnchor = null
+      lastTarget = null
+      if (isNew) return
+      if (currentHostId && currentHostId !== original.parentId) {
+        markHostDirty(currentHostId)
+      }
+      currentHostId = original.parentId
+      useScene.getState().updateNode(movingDoorNode.id, {
+        position: original.position,
+        rotation: original.rotation,
+        side: original.side,
+        parentId: original.parentId,
+        wallId: original.wallId,
+        roofSegmentId: original.roofSegmentId,
+        roofFace: original.roofFace,
+      })
+      if (original.parentId) markHostDirty(original.parentId)
+    }
+
+    const onCancel = () => {
+      useLiveTransforms.getState().clear(movingDoorNode.id)
+      if (isNew) {
+        useScene.getState().deleteNode(movingDoorNode.id)
+        if (currentHostId) markHostDirty(currentHostId)
+      } else {
+        useScene.getState().updateNode(movingDoorNode.id, {
+          position: original.position,
+          rotation: original.rotation,
+          side: original.side,
+          parentId: original.parentId,
+          wallId: original.wallId,
+          roofSegmentId: original.roofSegmentId,
+          roofFace: original.roofFace,
+          metadata: original.metadata,
+        })
+        if (original.parentId) markHostDirty(original.parentId)
       }
       useScene.temporal.getState().resume()
       hideCursor()
@@ -369,6 +530,10 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
     emitter.on('wall:move', onWallMove)
     emitter.on('wall:click', onWallClick)
     emitter.on('wall:leave', onWallLeave)
+    emitter.on('roof:enter', onRoofHover)
+    emitter.on('roof:move', onRoofHover)
+    emitter.on('roof:click', onRoofClick)
+    emitter.on('roof:leave', onRoofLeave)
     emitter.on('tool:cancel', onCancel)
 
     return () => {
@@ -379,7 +544,7 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
       if (currentMeta?.isTransient) {
         if (isNew) {
           useScene.getState().deleteNode(movingDoorNode.id)
-          if (currentWallId) markWallDirty(currentWallId)
+          if (currentHostId) markHostDirty(currentHostId)
         } else {
           useScene.getState().updateNode(movingDoorNode.id, {
             position: original.position,
@@ -387,9 +552,11 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
             side: original.side,
             parentId: original.parentId,
             wallId: original.wallId,
+            roofSegmentId: original.roofSegmentId,
+            roofFace: original.roofFace,
             metadata: original.metadata,
           })
-          if (original.parentId) markWallDirty(original.parentId)
+          if (original.parentId) markHostDirty(original.parentId)
         }
       }
       useLiveTransforms.getState().clear(movingDoorNode.id)
@@ -399,6 +566,10 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
       emitter.off('wall:move', onWallMove)
       emitter.off('wall:click', onWallClick)
       emitter.off('wall:leave', onWallLeave)
+      emitter.off('roof:enter', onRoofHover)
+      emitter.off('roof:move', onRoofHover)
+      emitter.off('roof:click', onRoofClick)
+      emitter.off('roof:leave', onRoofLeave)
       emitter.off('tool:cancel', onCancel)
     }
   }, [movingDoorNode, exitMoveMode])

packages/nodes/src/door/renderer.tsx

@@ -4,6 +4,7 @@ import { type DoorNode, useRegistry, useScene } from '@pascal-app/core'
 import { useNodeEvents } from '@pascal-app/viewer'
 import { useLayoutEffect, useRef } from 'react'
 import { type Mesh, MeshBasicMaterial } from 'three'
+import { RoofFaceHostFrame } from '../shared/roof-face-host'
 
 const doorHitboxMaterial = new MeshBasicMaterial({ visible: false })
 
@@ -17,7 +18,7 @@ export const DoorRenderer = ({ node }: { node: DoorNode }) => {
   const handlers = useNodeEvents(node, 'door')
   const isTransient = !!(node.metadata as Record<string, unknown> | null)?.isTransient
 
-  return (
+  const mesh = (
     <mesh
       castShadow
       material={doorHitboxMaterial}
@@ -31,6 +32,13 @@ export const DoorRenderer = ({ node }: { node: DoorNode }) => {
       <boxGeometry args={[0, 0, 0]} />
     </mesh>
   )
+
+  if (!node.roofSegmentId) return mesh
+  return (
+    <RoofFaceHostFrame roofFace={node.roofFace} roofSegmentId={node.roofSegmentId}>
+      {mesh}
+    </RoofFaceHostFrame>
+  )
 }
 
 export default DoorRenderer

packages/nodes/src/door/tool.tsx

@@ -4,6 +4,8 @@ import {
   DoorNode,
   emitter,
   isCurvedWall,
+  type RoofEvent,
+  type RoofNode,
   sceneRegistry,
   spatialGridManager,
   useScene,
@@ -22,6 +24,11 @@ import { useViewer } from '@pascal-app/viewer'
 import { useEffect, useRef } from 'react'
 import { BoxGeometry, EdgesGeometry, type Group, type LineSegments } from 'three'
 import { LineBasicNodeMaterial } from 'three/webgpu'
+import {
+  getRoofWallOpeningCursorPose,
+  type RoofWallOpeningTarget,
+  resolveRoofWallOpeningTarget,
+} from '../shared/roof-wall-opening-placement'
 import { resolveWallSlideAlignment } from '../shared/wall-opening-alignment'
 import { clampToWall, hasWallChildOverlap, wallLocalToWorld } from './door-math'
 
@@ -33,8 +40,10 @@ const edgeMaterial = new LineBasicNodeMaterial({
 })
 
 /**
- * Door tool — places DoorNodes on walls only.
- * Doors always sit at floor level (clampedY = height/2).
+ * Door tool — places DoorNodes on walls and on roof-segment wall faces
+ * (the generated base walls under a roof, including coplanar gable ends).
+ * Doors always sit at floor level (clampedY = height/2 — segment base for
+ * roof-hosted doors).
  */
 const DoorTool: React.FC = () => {
   const draftRef = useRef<DoorNode | null>(null)
@@ -56,8 +65,8 @@ const DoorTool: React.FC = () => {
         wallEvent.node.end,
       )
 
-    const markWallDirty = (wallId: string) => {
-      useScene.getState().dirtyNodes.add(wallId as AnyNodeId)
+    const markHostDirty = (hostId: string) => {
+      useScene.getState().dirtyNodes.add(hostId as AnyNodeId)
     }
 
     const destroyDraft = () => {
@@ -65,7 +74,7 @@ const DoorTool: React.FC = () => {
       const wallId = draftRef.current.parentId
       useScene.getState().deleteNode(draftRef.current.id)
       draftRef.current = null
-      if (wallId) markWallDirty(wallId)
+      if (wallId) markHostDirty(wallId)
     }
 
     const hideCursor = () => {
@@ -207,7 +216,7 @@ const DoorTool: React.FC = () => {
             rotation: [0, itemRotation, 0],
             side,
           })
-          markWallDirty(event.node.id)
+          markHostDirty(event.node.id)
         } else {
           useScene.getState().updateNode(draftRef.current.id, {
             position: [clampedX, clampedY, 0],
@@ -215,6 +224,9 @@ const DoorTool: React.FC = () => {
             side,
             parentId: event.node.id,
             wallId: event.node.id,
+            // The draft may arrive from a roof-segment face hover.
+            roofSegmentId: undefined,
+            roofFace: undefined,
           })
         }
       }
@@ -335,6 +347,126 @@ const DoorTool: React.FC = () => {
       hideCursor()
     }
 
+    // ── Roof-segment wall faces ─────────────────────────────────────
+    // The merged roof mesh emits `roof:*`; hits are resolved against the
+    // segments' vertical wall faces (base walls + coplanar gable ends).
+
+    const resolveRoofTarget = (event: RoofEvent) =>
+      resolveRoofWallOpeningTarget({
+        event,
+        width: draftRef.current?.width ?? 0.9,
+        height: draftRef.current?.height ?? 2.1,
+        ignoreId: draftRef.current?.id,
+        vertical: { kind: 'bottom-locked' },
+      })
+
+    const updateRoofCursor = (target: RoofWallOpeningTarget, roof: RoofNode) => {
+      const pose = getRoofWallOpeningCursorPose(target, roof)
+      if (pose) updateCursor(pose.position, pose.rotationY, target.valid)
+    }
+
+    const onRoofHover = (event: RoofEvent) => {
+      const target = resolveRoofTarget(event)
+      if (!target) {
+        // On the roof but not over a placeable wall face (slope, soffit,
+        // or a face the door cannot fit on).
+        if (draftRef.current?.roofSegmentId) {
+          destroyDraft()
+          hideCursor()
+        }
+        return
+      }
+      const { segment, face, position } = target
+
+      if (draftRef.current && draftRef.current.parentId !== segment.id) destroyDraft()
+      if (draftRef.current) {
+        useScene.getState().updateNode(draftRef.current.id, {
+          position,
+          rotation: [0, 0, 0],
+          roofFace: face.id,
+        })
+      } else {
+        const node = DoorNode.parse({
+          position,
+          rotation: [0, 0, 0],
+          side: 'front',
+          roofSegmentId: segment.id,
+          roofFace: face.id,
+          parentId: segment.id,
+          metadata: { isTransient: true },
+        })
+        useScene.getState().createNode(node, segment.id as AnyNodeId)
+        draftRef.current = node
+      }
+      updateRoofCursor(target, event.node as RoofNode)
+      event.stopPropagation()
+    }
+
+    const onRoofClick = (event: RoofEvent) => {
+      if (!draftRef.current?.roofSegmentId) return
+      const target = resolveRoofTarget(event)
+      if (!target?.valid) return
+      const { segment, face, position } = target
+
+      const draft = draftRef.current
+      draftRef.current = null
+
+      useScene.getState().deleteNode(draft.id)
+      useScene.temporal.getState().resume()
+
+      const state = useScene.getState()
+      const doorCount = Object.values(state.nodes).filter(
+        (n) => n.type === 'door' && (n as DoorNode).roofSegmentId !== undefined,
+      ).length
+
+      const node = DoorNode.parse({
+        name: `Door ${doorCount + 1}`,
+        position,
+        rotation: [0, 0, 0],
+        side: 'front',
+        roofSegmentId: segment.id,
+        roofFace: face.id,
+        parentId: segment.id,
+        width: draft.width,
+        height: draft.height,
+        doorCategory: draft.doorCategory,
+        doorType: draft.doorType,
+        leafCount: draft.leafCount,
+        operationState: draft.operationState,
+        slideDirection: draft.slideDirection,
+        trackStyle: draft.trackStyle,
+        garagePanelCount: draft.garagePanelCount,
+        frameThickness: draft.frameThickness,
+        frameDepth: draft.frameDepth,
+        threshold: draft.threshold,
+        thresholdHeight: draft.thresholdHeight,
+        hingesSide: draft.hingesSide,
+        swingDirection: draft.swingDirection,
+        segments: draft.segments,
+        handle: draft.handle,
+        handleHeight: draft.handleHeight,
+        handleSide: draft.handleSide,
+        doorCloser: draft.doorCloser,
+        panicBar: draft.panicBar,
+        panicBarHeight: draft.panicBarHeight,
+      })
+
+      useScene.getState().createNode(node, segment.id as AnyNodeId)
+      // Rebuild the segment (and the merged roof) so the wall brush
+      // picks up the new opening cut.
+      useScene.getState().dirtyNodes.add(segment.id as AnyNodeId)
+      useViewer.getState().setSelection({ selectedIds: [node.id] })
+      useScene.temporal.getState().pause()
+      triggerSFX('sfx:structure-build')
+      event.stopPropagation()
+    }
+
+    const onRoofLeave = () => {
+      if (!draftRef.current?.roofSegmentId) return
+      destroyDraft()
+      hideCursor()
+    }
+
     const onCancel = () => {
       destroyDraft()
       hideCursor()
@@ -344,6 +476,10 @@ const DoorTool: React.FC = () => {
     emitter.on('wall:move', onWallMove)
     emitter.on('wall:click', onWallClick)
     emitter.on('wall:leave', onWallLeave)
+    emitter.on('roof:enter', onRoofHover)
+    emitter.on('roof:move', onRoofHover)
+    emitter.on('roof:click', onRoofClick)
+    emitter.on('roof:leave', onRoofLeave)
     emitter.on('tool:cancel', onCancel)
 
     return () => {
@@ -355,6 +491,10 @@ const DoorTool: React.FC = () => {
       emitter.off('wall:move', onWallMove)
       emitter.off('wall:click', onWallClick)
       emitter.off('wall:leave', onWallLeave)
+      emitter.off('roof:enter', onRoofHover)
+      emitter.off('roof:move', onRoofHover)
+      emitter.off('roof:click', onRoofClick)
+      emitter.off('roof:leave', onRoofLeave)
       emitter.off('tool:cancel', onCancel)
     }
   }, [])

packages/nodes/src/item/definition.ts

@@ -206,12 +206,13 @@ export const itemDefinition: NodeDefinition<typeof ItemNode> = {
     // siblings of GLB items inside the unified `items` table.
     //
     // Items can be hosted on walls (assets with `attachTo: 'wall'`)
-    // via `wallId` + `wallT`. When a composition that includes a
-    // wall-hosted item is saved as a preset (a sconce, a hanging
-    // shelf, etc.), the host app strips these via `getHostRefFields(def)`
-    // so the descendant re-attaches against the new wall geometry at
+    // via `wallId` + `wallT`, or on a roof-segment wall face via
+    // `roofSegmentId`. When a composition that includes a wall-hosted
+    // item is saved as a preset (a sconce, a hanging shelf, etc.), the
+    // host app strips these via `getHostRefFields(def)` so the
+    // descendant re-attaches against the new host geometry at
     // placement time.
-    hostRefFields: ['wallId', 'wallT'],
+    hostRefFields: ['wallId', 'wallT', 'roofSegmentId', 'roofFace'],
     // Floor items get lifted by slabs underneath via the generic
     // `<FloorElevationSystem>`. Wall- / ceiling-attached items live in
     // their parent's local frame and skip the lift via `applies`.

packages/nodes/src/item/floorplan-move.ts

@@ -5,9 +5,12 @@ import {
   collectAlignmentAnchors,
   type FloorplanMoveTarget,
   type FloorplanMoveTargetSession,
+  getRoofWallFaceFrame,
   getScaledDimensions,
   type ItemNode,
   movingFootprintAnchors,
+  type RoofSegmentNode,
+  roofFacePointToSegment,
   useScene,
 } from '@pascal-app/core'
 import { applyFloorplanAlignment, useEditor, type WallPlanPoint } from '@pascal-app/editor'
@@ -95,6 +98,31 @@ function resolveItemPlanTransform(
       point: [parentTransform.point[0] + offsetX, parentTransform.point[1] + offsetZ],
       rotation: parentTransform.rotation + localRotation,
     }
+  } else if (parent?.type === 'roof-segment') {
+    // Roof-hosted wall item: FACE-LOCAL position mapped through the face
+    // frame, then composed through the segment's and roof's yaw +
+    // position into level-local plan coords — without this the drag seed
+    // jumps off the roof at move start.
+    const segment = parent as RoofSegmentNode
+    const roof = segment.parentId
+      ? (nodes[segment.parentId as AnyNodeId] as
+          | (AnyNode & { position: [number, number, number]; rotation: number })
+          | undefined)
+      : undefined
+    if (roof?.type === 'roof' && item.roofFace) {
+      const frame = getRoofWallFaceFrame(segment, item.roofFace)
+      const segLocal = roofFacePointToSegment(segment, item.roofFace, item.position)
+      const [sx, sz] = rotateVec(segLocal[0], segLocal[2], segment.rotation ?? 0)
+      const [rx, rz] = rotateVec(
+        sx + segment.position[0],
+        sz + segment.position[2],
+        roof.rotation ?? 0,
+      )
+      result = {
+        point: [rx + roof.position[0], rz + roof.position[2]],
+        rotation: (roof.rotation ?? 0) + (segment.rotation ?? 0) + frame.yaw + localRotation,
+      }
+    }
   }
 
   cache.set(item.id as AnyNodeId, result)
@@ -208,6 +236,10 @@ function buildWallItemSession(
             rotation: [0, hit.itemRotation, 0],
             side: hit.side,
             parentId: hit.wall.id,
+            // Re-anchoring to a wall ends any roof-segment hosting; the
+            // overlay's snapshot restores it if the move is reverted.
+            roofSegmentId: undefined,
+            roofFace: undefined,
           },
         },
       ])

packages/nodes/src/item/floorplan.ts

@@ -4,8 +4,11 @@ import {
   type FloorplanGeometry,
   type FloorplanPoint,
   type GeometryContext,
+  getRoofWallFaceFrame,
   getScaledDimensions,
   type ItemNode,
+  type RoofSegmentNode,
+  roofFacePointToSegment,
   useLiveTransforms,
 } from '@pascal-app/core'
 
@@ -112,6 +115,31 @@ function resolveItemTransform(
       y: shelfZ + offsetY,
       rotation: shelfRotationY + localRotation,
     }
+  } else if (parentNode?.type === 'roof-segment') {
+    // Roof-hosted wall item: FACE-LOCAL position mapped through the face
+    // frame, then composed through the segment's and parent roof's poses
+    // into level-local plan coords.
+    const segment = parentNode as RoofSegmentNode
+    const roof = segment.parentId
+      ? (ctx.resolve(segment.parentId as AnyNodeId) as
+          | (AnyNode & { position: [number, number, number]; rotation: number })
+          | undefined)
+      : undefined
+    if (roof?.type === 'roof' && item.roofFace) {
+      const frame = getRoofWallFaceFrame(segment, item.roofFace)
+      const segLocal = roofFacePointToSegment(segment, item.roofFace, item.position)
+      const [sx, sz] = rotateVec(segLocal[0], segLocal[2], segment.rotation ?? 0)
+      const [rx, rz] = rotateVec(
+        sx + segment.position[0],
+        sz + segment.position[2],
+        roof.rotation ?? 0,
+      )
+      result = {
+        x: rx + roof.position[0],
+        y: rz + roof.position[2],
+        rotation: (roof.rotation ?? 0) + (segment.rotation ?? 0) + frame.yaw + localRotation,
+      }
+    }
   } else {
     // Level / slab / ceiling parent — item.position is level-local.
     result = {

packages/nodes/src/item/move-tool.tsx

@@ -38,9 +38,20 @@ import { Vector3 } from 'three'
 function getInitialState(node: ItemNode): PlacementState {
   const attachTo = node.asset.attachTo
   if (attachTo === 'wall' || attachTo === 'wall-side') {
+    if (node.roofSegmentId) {
+      return {
+        surface: 'roof-wall',
+        wallId: null,
+        roofSegmentId: node.roofSegmentId,
+        ceilingId: null,
+        surfaceItemId: null,
+        shelfId: null,
+      }
+    }
     return {
       surface: 'wall',
       wallId: node.parentId,
+      roofSegmentId: null,
       ceilingId: null,
       surfaceItemId: null,
       shelfId: null,
@@ -50,6 +61,7 @@ function getInitialState(node: ItemNode): PlacementState {
     return {
       surface: 'ceiling',
       wallId: null,
+      roofSegmentId: null,
       ceilingId: node.parentId,
       surfaceItemId: null,
       shelfId: null,
@@ -58,6 +70,7 @@ function getInitialState(node: ItemNode): PlacementState {
   return {
     surface: 'floor',
     wallId: null,
+    roofSegmentId: null,
     ceilingId: null,
     surfaceItemId: null,
     shelfId: null,
@@ -81,6 +94,7 @@ export function MoveItemTool({ node }: { node: ItemNode }) {
       ? {
           surface: 'floor',
           wallId: null,
+          roofSegmentId: null,
           ceilingId: null,
           surfaceItemId: null,
           shelfId: null,

packages/nodes/src/item/renderer.tsx

@@ -34,6 +34,7 @@ import { Suspense, useEffect, useMemo, useRef } from 'react'
 import type { AnimationAction, Group, Material, Mesh } from 'three'
 import { MathUtils } from 'three'
 import { positionLocal, smoothstep, time } from 'three/tsl'
+import { RoofFaceHostFrame } from '../shared/roof-face-host'
 
 type MutableMaterial = Material & {
   depthTest?: boolean
@@ -95,7 +96,7 @@ export const ItemRenderer = ({ node: storeNode }: { node: ItemNode }) => {
   const roomClearPreview =
     (node as ItemNode & { roomClearPreview?: unknown }).roomClearPreview === true
 
-  return (
+  const content = (
     <group position={node.position} ref={ref} rotation={node.rotation} visible={node.visible}>
       {roomClearPreview ? (
         <ClearPreviewModel node={node} />
@@ -113,6 +114,13 @@ export const ItemRenderer = ({ node: storeNode }: { node: ItemNode }) => {
       )}
     </group>
   )
+
+  if (!node.roofSegmentId) return content
+  return (
+    <RoofFaceHostFrame roofFace={node.roofFace} roofSegmentId={node.roofSegmentId}>
+      {content}
+    </RoofFaceHostFrame>
+  )
 }
 
 const previewOpacity = smoothstep(0.42, 0.55, positionLocal.y.add(time.mul(-0.2)).mul(10).fract())

packages/nodes/src/shared/placeholder-geometry.ts

@@ -13,13 +13,17 @@ import { BufferGeometry, Float32BufferAttribute } from 'three'
  * (count 0) makes three.js create no GPU buffer for it, so vertex buffer slot 0
  * is never bound and WebGPU rejects the draw with "Vertex buffer slot 0 … was
  * not set", which poisons the whole command encoder (cascading into "Invalid
- * CommandBuffer" on every queue submit). Three real vertices give it a bound
- * buffer; the `groupCount` count-0 groups keep nothing drawn while matching the
- * mesh's material-array length so raycasts / BVH never index past the materials.
+ * CommandBuffer" on every queue submit). The zero normals and UVs keep lit
+ * node-material pipelines from compiling additional required-but-unbound
+ * vertex buffers. Three real vertices give it bound buffers; the `groupCount`
+ * count-0 groups keep nothing drawn while matching the mesh's material-array
+ * length so raycasts / BVH never index past the materials.
  */
 export function createPlaceholderGeometry(groupCount = 0): BufferGeometry {
   const geometry = new BufferGeometry()
   geometry.setAttribute('position', new Float32BufferAttribute(new Float32Array(9), 3))
+  geometry.setAttribute('normal', new Float32BufferAttribute(new Float32Array(9), 3))
+  geometry.setAttribute('uv', new Float32BufferAttribute(new Float32Array(6), 2))
   for (let group = 0; group < groupCount; group++) {
     geometry.addGroup(0, 0, group)
   }

packages/nodes/src/shared/polygon-vertex-affordance.ts

@@ -1,6 +1,8 @@
 import {
+  type AnyNode,
   type AnyNodeId,
   type FloorplanAffordance,
+  type FloorplanAffordanceModifiers,
   type FloorplanAffordanceSession,
   useScene,
 } from '@pascal-app/core'
@@ -41,6 +43,22 @@ export type EdgeDragPayload = {
   edgeIndex: number
 }
 
+type PolygonAffordanceMode = 'move-vertex' | 'add-vertex' | 'move-edge'
+
+export type PolygonAffordanceSnapContext<N extends PolygonShape & { id: AnyNodeId }> = {
+  node: N
+  nodes: Record<AnyNodeId, AnyNode>
+  rawPoint: WallPlanPoint
+  fallbackPoint: WallPlanPoint
+  modifiers: FloorplanAffordanceModifiers
+  holeIndex?: number
+  mode: PolygonAffordanceMode
+}
+
+type PolygonAffordanceOptions<N extends PolygonShape & { id: AnyNodeId }> = {
+  resolvePlanPoint?: (context: PolygonAffordanceSnapContext<N>) => WallPlanPoint
+}
+
 type PolygonShape = {
   polygon: ReadonlyArray<readonly [number, number]>
   holes?: ReadonlyArray<ReadonlyArray<readonly [number, number]>>
@@ -76,11 +94,19 @@ function buildRingPatch(
   return { holes: nextHoles }
 }
 
+function resolveAffordancePlanPoint<N extends PolygonShape & { id: AnyNodeId }>(
+  options: PolygonAffordanceOptions<N> | undefined,
+  context: PolygonAffordanceSnapContext<N>,
+): WallPlanPoint {
+  return options?.resolvePlanPoint?.(context) ?? context.fallbackPoint
+}
+
 export function createPolygonVertexAffordance<N extends PolygonShape & { id: AnyNodeId }>(
   kind: string,
+  options?: PolygonAffordanceOptions<N>,
 ): FloorplanAffordance<N> {
   return {
-    start({ node, payload }): FloorplanAffordanceSession {
+    start({ node, payload, nodes }): FloorplanAffordanceSession {
       const { vertexIndex, holeIndex } = payload as PolygonVertexPayload
       const originalRing = getRing(node, holeIndex)
       if (!originalRing) {
@@ -96,9 +122,17 @@ export function createPolygonVertexAffordance<N extends PolygonShape & { id: Any
       return {
         affectedIds: [node.id],
         apply({ planPoint, modifiers }) {
-          const snapped: WallPlanPoint = modifiers.shiftKey
-            ? (planPoint as WallPlanPoint)
-            : snapPointToGrid(planPoint as WallPlanPoint)
+          const rawPoint: WallPlanPoint = [planPoint[0], planPoint[1]]
+          const fallbackPoint = modifiers.shiftKey ? rawPoint : snapPointToGrid(rawPoint)
+          const snapped = resolveAffordancePlanPoint(options, {
+            node,
+            nodes,
+            rawPoint,
+            fallbackPoint,
+            modifiers,
+            holeIndex,
+            mode: 'move-vertex',
+          })
           const nextRing: [number, number][] = originalRing.map((p, i) =>
             i === vertexIndex ? [snapped[0], snapped[1]] : p,
           )
@@ -128,9 +162,10 @@ export function createPolygonVertexAffordance<N extends PolygonShape & { id: Any
  */
 export function createPolygonAddVertexAffordance<N extends PolygonShape & { id: AnyNodeId }>(
   kind: string,
+  options?: PolygonAffordanceOptions<N>,
 ): FloorplanAffordance<N> {
   return {
-    start({ node, payload }): FloorplanAffordanceSession {
+    start({ node, payload, nodes }): FloorplanAffordanceSession {
       const { edgeIndex, holeIndex } = payload as AddVertexPayload
       const originalRing = getRing(node, holeIndex)
       if (!originalRing) {
@@ -171,9 +206,17 @@ export function createPolygonAddVertexAffordance<N extends PolygonShape & { id:
       return {
         affectedIds: [node.id],
         apply({ planPoint, modifiers }) {
-          const snapped: WallPlanPoint = modifiers.shiftKey
-            ? (planPoint as WallPlanPoint)
-            : snapPointToGrid(planPoint as WallPlanPoint)
+          const rawPoint: WallPlanPoint = [planPoint[0], planPoint[1]]
+          const fallbackPoint = modifiers.shiftKey ? rawPoint : snapPointToGrid(rawPoint)
+          const snapped = resolveAffordancePlanPoint(options, {
+            node,
+            nodes,
+            rawPoint,
+            fallbackPoint,
+            modifiers,
+            holeIndex,
+            mode: 'add-vertex',
+          })
           const nextRing: [number, number][] = initialRing.map((p, i) =>
             i === newVertexIndex ? [snapped[0], snapped[1]] : p,
           )
@@ -204,9 +247,10 @@ export function createPolygonAddVertexAffordance<N extends PolygonShape & { id:
  */
 export function createPolygonMoveEdgeAffordance<N extends PolygonShape & { id: AnyNodeId }>(
   kind: string,
+  options?: PolygonAffordanceOptions<N>,
 ): FloorplanAffordance<N> {
   return {
-    start({ node, payload, initialPlanPoint }): FloorplanAffordanceSession {
+    start({ node, payload, initialPlanPoint, nodes }): FloorplanAffordanceSession {
       const { edgeIndex, holeIndex } = payload as EdgeDragPayload
       const originalRing = getRing(node, holeIndex)
       if (!originalRing) {
@@ -254,17 +298,33 @@ export function createPolygonMoveEdgeAffordance<N extends PolygonShape & { id: A
         apply({ planPoint, modifiers }) {
           // Project the pointer delta onto the edge normal — that's the
           // signed perpendicular distance the edge should travel.
-          const deltaX = planPoint[0] - startX
-          const deltaY = planPoint[1] - startY
+          const rawPoint: WallPlanPoint = [planPoint[0], planPoint[1]]
+          const deltaX = rawPoint[0] - startX
+          const deltaY = rawPoint[1] - startY
           let projection = deltaX * normalX + deltaY * normalY
           if (!modifiers.shiftKey) {
             // Snap the projection scalar to a 0.5m grid (legacy uses the
             // same half-meter snap for slab edges).
             projection = Math.round(projection * 2) / 2
           }
+          const fallbackPoint: WallPlanPoint = [
+            startX + normalX * projection,
+            startY + normalY * projection,
+          ]
+          const snappedPoint = resolveAffordancePlanPoint(options, {
+            node,
+            nodes,
+            rawPoint,
+            fallbackPoint,
+            modifiers,
+            holeIndex,
+            mode: 'move-edge',
+          })
+          const normalDistance =
+            (snappedPoint[0] - startX) * normalX + (snappedPoint[1] - startY) * normalY
           const nextRing: [number, number][] = originalRing.map((p, i) => {
             if (i === edgeStartIndex || i === edgeEndIndex) {
-              return [p[0] + normalX * projection, p[1] + normalY * projection]
+              return [p[0] + normalX * normalDistance, p[1] + normalY * normalDistance]
             }
             return [p[0], p[1]] as [number, number]
           })

packages/nodes/src/shared/roof-face-host.tsx

@@ -0,0 +1,53 @@
+'use client'
+
+import {
+  type AnyNodeId,
+  getRoofWallFaceFrame,
+  type RoofSegmentNode,
+  type RoofWallFaceId,
+  useLiveNodeOverrides,
+  useScene,
+} from '@pascal-app/core'
+import { type ReactNode, useMemo } from 'react'
+
+/**
+ * Mounts a roof-hosted wall child inside its host face frame. Children
+ * of roof segments render under the roof's `roof-elements` group (roof
+ * frame); this wrapper applies the segment transform plus the face
+ * frame, both derived from the LIVE-override-merged segment — hosted
+ * nodes therefore track segment handle drags in real time instead of
+ * jumping to their new spot on commit. Inside the frame, children use
+ * plain wall-child position conventions ([u, v, z-from-mid-plane]).
+ */
+export function RoofFaceHostFrame({
+  roofSegmentId,
+  roofFace,
+  children,
+}: {
+  roofSegmentId: string
+  roofFace: RoofWallFaceId | undefined
+  children: ReactNode
+}) {
+  const storeSegment = useScene(
+    (state) => state.nodes[roofSegmentId as AnyNodeId] as RoofSegmentNode | undefined,
+  )
+  const liveOverride = useLiveNodeOverrides((s) => s.get(roofSegmentId as AnyNodeId))
+  const segment = useMemo(
+    () =>
+      storeSegment && liveOverride
+        ? ({ ...storeSegment, ...liveOverride } as RoofSegmentNode)
+        : storeSegment,
+    [storeSegment, liveOverride],
+  )
+
+  if (!segment || segment.type !== 'roof-segment' || !roofFace) return null
+  const frame = getRoofWallFaceFrame(segment, roofFace)
+
+  return (
+    <group position={segment.position} rotation-y={segment.rotation}>
+      <group position={frame.origin} rotation-y={frame.yaw}>
+        {children}
+      </group>
+    </group>
+  )
+}

packages/nodes/src/shared/roof-opening-host.ts

@@ -0,0 +1,120 @@
+import type {
+  AnyNode,
+  AnyNodeId,
+  RoofNode,
+  RoofSegmentNode,
+  RoofWallFaceId,
+} from '@pascal-app/core'
+import {
+  getMaxRoofRectHeightFromAnchor,
+  getMaxRoofRectWidthFromAnchor,
+  getRoofSegmentWallFace,
+  roofFacePointToSegment,
+} from '@pascal-app/core'
+
+/**
+ * Host-side helpers for openings (door / window) hosted on a roof-segment
+ * wall face: resize-handle limits derived from the face profile, and the
+ * plan-space anchors the 2D floor-plan move path needs. Hosted children
+ * store FACE-LOCAL coords ([u, v, z-from-mid-plane]) + `roofFace`.
+ */
+
+type RoofHostedOpening = {
+  roofSegmentId?: string
+  roofFace?: RoofWallFaceId
+  parentId: string | null
+  position: [number, number, number]
+  width: number
+  height: number
+}
+
+type SceneReader = { get: (id: AnyNodeId) => unknown }
+
+function resolveHostFace(node: RoofHostedOpening, scene: SceneReader) {
+  if (!(node.roofSegmentId && node.roofFace)) return null
+  const segment = scene.get(node.roofSegmentId as AnyNodeId) as RoofSegmentNode | undefined
+  if (!segment || segment.type !== 'roof-segment') return null
+  return { segment, face: getRoofSegmentWallFace(segment, node.roofFace) }
+}
+
+/**
+ * Resize-handle width limit for a roof-hosted opening: the opposite edge
+ * is anchored, `growSign` (+1 = door-local +X arrow) is the direction
+ * the dragged edge moves. Null when the node is not roof-hosted.
+ */
+export function readRoofFaceWidthMax(
+  node: RoofHostedOpening,
+  scene: SceneReader,
+  growSign: number,
+): number | null {
+  const host = resolveHostFace(node, scene)
+  if (!host) return null
+  const anchorU = node.position[0] - (growSign * node.width) / 2
+  return getMaxRoofRectWidthFromAnchor(host.face, anchorU, growSign, node.position[1], node.height)
+}
+
+/**
+ * Resize-handle height limit for a roof-hosted opening. `growSign` +1 =
+ * bottom edge anchored, top grows up; -1 = top anchored, bottom grows
+ * down. Null when the node is not roof-hosted.
+ */
+export function readRoofFaceHeightMax(
+  node: RoofHostedOpening,
+  scene: SceneReader,
+  growSign: number,
+): number | null {
+  const host = resolveHostFace(node, scene)
+  if (!host) return null
+  const anchorV = node.position[1] - (growSign * node.height) / 2
+  return getMaxRoofRectHeightFromAnchor(host.face, node.position[0], node.width, anchorV, growSign)
+}
+
+/**
+ * Level hosting a roof-hosted opening's roof (opening → segment → roof →
+ * level). Null when the parent chain isn't roof-shaped.
+ */
+export function getRoofHostedOpeningLevelId(
+  node: { parentId: string | null },
+  nodes: Record<string, AnyNode | undefined>,
+): AnyNodeId | null {
+  const segment = node.parentId ? nodes[node.parentId] : undefined
+  if (segment?.type !== 'roof-segment') return null
+  const roof = segment.parentId ? nodes[segment.parentId] : undefined
+  if (roof?.type !== 'roof') return null
+  return (roof.parentId as AnyNodeId | null) ?? null
+}
+
+/**
+ * Level-plan [x, z] of a roof-hosted node — its face-local center mapped
+ * through the face frame, then composed through the segment's and roof's
+ * yaw + position.
+ */
+export function getRoofHostedOpeningPlanPoint(
+  node: {
+    parentId: string | null
+    roofFace?: RoofWallFaceId
+    position: [number, number, number]
+  },
+  nodes: Record<string, AnyNode | undefined>,
+): [number, number] | null {
+  const segment = node.parentId ? (nodes[node.parentId] as RoofSegmentNode | undefined) : undefined
+  if (segment?.type !== 'roof-segment' || !node.roofFace) return null
+  const roof = segment.parentId ? (nodes[segment.parentId] as RoofNode | undefined) : undefined
+  if (roof?.type !== 'roof') return null
+
+  const rotate = (x: number, z: number, yaw: number): [number, number] => [
+    x * Math.cos(yaw) + z * Math.sin(yaw),
+    -x * Math.sin(yaw) + z * Math.cos(yaw),
+  ]
+
+  const segLocal = roofFacePointToSegment(segment, node.roofFace, [
+    node.position[0],
+    node.position[1],
+    node.position[2],
+  ])
+  const [sx, sz] = rotate(segLocal[0], segLocal[2], segment.rotation ?? 0)
+  const segX = sx + segment.position[0]
+  const segZ = sz + segment.position[2]
+  const [rx, rz] = rotate(segX, segZ, roof.rotation ?? 0)
+  return [rx + roof.position[0], rz + roof.position[2]]
+}

packages/nodes/src/shared/roof-wall-opening-cut.ts

@@ -0,0 +1,50 @@
+import type { RoofSegmentNode, RoofWallFaceId } from '@pascal-app/core'
+import { getRoofWallFaceFrame, roofFacePointToSegment } from '@pascal-app/core'
+import * as THREE from 'three'
+
+type RoofWallOpening = {
+  roofSegmentId?: string
+  roofFace?: RoofWallFaceId
+  position: [number, number, number]
+  width: number
+  height: number
+}
+
+/**
+ * CSG cut for a door / window hosted on a roof-segment wall face
+ * (`capabilities.roofAccessory.buildCut`). A box through the wall
+ * mid-plane, derived from the CURRENT host geometry (the opening stores
+ * face-local coords), so the hole follows segment resizes for free.
+ *
+ * Returns null for wall-hosted openings: their cut is handled by the
+ * wall system's own cutout pipeline.
+ */
+export function buildRoofWallOpeningCut(
+  node: RoofWallOpening,
+  hostSegment: RoofSegmentNode,
+): THREE.BufferGeometry | null {
+  if (!node.roofSegmentId || !node.roofFace) return null
+
+  const wallThickness = hostSegment.wallThickness ?? 0.1
+  // Through the wall both ways, but well short of the rake/eave overhang
+  // so the cut never nicks the soffit or fascia bands.
+  const depth = wallThickness * 2 + 0.04
+
+  // A door's cut bottom is coplanar with the wall brush base — extend it
+  // slightly downward so three-bvh-csg never has to clip coplanar faces.
+  const bottom = node.position[1] - node.height / 2
+  const bottomPad = bottom < 0.005 ? 0.02 : 0
+
+  const center = roofFacePointToSegment(hostSegment, node.roofFace, [
+    node.position[0],
+    node.position[1],
+    0,
+  ])
+  const { yaw } = getRoofWallFaceFrame(hostSegment, node.roofFace)
+
+  const geo = new THREE.BoxGeometry(node.width, node.height + bottomPad, depth)
+  geo.translate(0, -bottomPad / 2, 0)
+  geo.rotateY(yaw)
+  geo.translate(center[0], center[1], center[2])
+  return geo
+}

packages/nodes/src/shared/roof-wall-opening-placement.ts

@@ -0,0 +1,113 @@
+import {
+  type AnyNodeId,
+  clampRectToRoofWallFace,
+  type RoofEvent,
+  type RoofNode,
+  type RoofSegmentNode,
+  type RoofSegmentWallFace,
+  roofFacePointToSegment,
+  sceneRegistry,
+} from '@pascal-app/core'
+import { hasRoofFaceChildOverlap, resolveRoofWallHit } from '@pascal-app/editor'
+import { useViewer } from '@pascal-app/viewer'
+import { Vector3 } from 'three'
+
+/**
+ * Stateless target/cursor math shared by the door and window placement
+ * + move tools' roof flows. The tools keep ownership of everything
+ * stateful (draft lifecycle, undo/temporal sequencing, commit field
+ * lists, SFX/selection) — only the settled geometry lives here.
+ */
+
+export type RoofWallOpeningTarget = {
+  segment: RoofSegmentNode
+  face: RoofSegmentWallFace
+  /** FACE-LOCAL stored position: [u, v-center, 0] on the wall mid-plane. */
+  position: [number, number, number]
+  /** False when the rect overlaps a sibling on the same face. */
+  valid: boolean
+}
+
+export type RoofWallOpeningVertical =
+  /** Doors: bottom on the segment base, only `u` slides. */
+  | { kind: 'bottom-locked' }
+  /** Windows: free height, optionally grid-snapped before the clamp. */
+  | { kind: 'free'; snap?: (v: number) => number }
+
+/**
+ * Resolve a roof pointer event to an opening placement on a segment
+ * wall face: hit → vertical policy → profile clamp → overlap check.
+ * Null when the pointer isn't over a placeable face or the rect cannot
+ * fit at that spot.
+ */
+export function resolveRoofWallOpeningTarget(args: {
+  event: RoofEvent
+  width: number
+  height: number
+  ignoreId?: string
+  vertical: RoofWallOpeningVertical
+}): RoofWallOpeningTarget | null {
+  const { event, width, height, ignoreId, vertical } = args
+  const hit = resolveRoofWallHit(event.node as RoofNode, event.position, event.normal, event.object)
+  if (!hit) return null
+
+  const centerV = vertical.kind === 'bottom-locked' ? height / 2 : (vertical.snap?.(hit.v) ?? hit.v)
+  const clamped = clampRectToRoofWallFace(
+    hit.face,
+    hit.u,
+    centerV,
+    width,
+    height,
+    vertical.kind === 'bottom-locked' ? { lockV: true } : undefined,
+  )
+  if (!clamped) return null
+
+  const valid = !hasRoofFaceChildOverlap(
+    hit.segment,
+    hit.face.id,
+    clamped.u,
+    clamped.v,
+    width,
+    height,
+    ignoreId,
+  )
+  return {
+    segment: hit.segment,
+    face: hit.face,
+    position: [clamped.u, clamped.v, 0],
+    valid,
+  }
+}
+
+const cursorPoint = new Vector3()
+
+/**
+ * World → building-local. Tool cursor groups render inside the
+ * building's frame (same conversion as the roof accessory tools).
+ */
+export function worldToSelectedBuildingLocal(point: Vector3): [number, number, number] {
+  const buildingId = useViewer.getState().selection.buildingId
+  const buildingObj = buildingId ? sceneRegistry.nodes.get(buildingId as AnyNodeId) : undefined
+  if (buildingObj) buildingObj.worldToLocal(point)
+  return [point.x, point.y, point.z]
+}
+
+/**
+ * Cursor pose for a resolved target: building-local position of the
+ * opening center + total yaw (roof ∘ segment ∘ face).
+ */
+export function getRoofWallOpeningCursorPose(
+  target: RoofWallOpeningTarget,
+  roof: RoofNode,
+): { position: [number, number, number]; rotationY: number } | null {
+  const segObj = sceneRegistry.nodes.get(target.segment.id as AnyNodeId)
+  if (!segObj) return null
+  segObj.updateWorldMatrix(true, false)
+  const segLocal = roofFacePointToSegment(target.segment, target.face.id, target.position)
+  cursorPoint.set(segLocal[0], segLocal[1], segLocal[2])
+  segObj.localToWorld(cursorPoint)
+  return {
+    position: worldToSelectedBuildingLocal(cursorPoint),
+    rotationY: (roof.rotation ?? 0) + (target.segment.rotation ?? 0) + target.face.yaw,
+  }
+}

packages/nodes/src/site/renderer.tsx

@@ -15,8 +15,15 @@ import {
   useNodeEvents,
   useViewer,
 } from '@pascal-app/viewer'
-import { useMemo, useRef } from 'react'
-import { BufferGeometry, Float32BufferAttribute, type Group, Path, Shape } from 'three'
+import { useEffect, useMemo, useRef } from 'react'
+import {
+  BufferGeometry,
+  Float32BufferAttribute,
+  type Group,
+  Path,
+  Shape,
+  ShapeGeometry,
+} from 'three'
 import { MeshLambertNodeMaterial } from 'three/webgpu'
 
 const Y_OFFSET = 0.01
@@ -134,6 +141,13 @@ export const SiteRenderer = ({ node }: { node: SiteNode }) => {
     if (!polygonPoints || polygonPoints.length < 2) return null
     return createBoundaryLineGeometry(polygonPoints)
   }, [polygonPoints])
+  useEffect(() => () => lineGeometry?.dispose(), [lineGeometry])
+
+  const groundGeometry = useMemo(() => {
+    if (!groundShape) return null
+    return new ShapeGeometry(groundShape)
+  }, [groundShape])
+  useEffect(() => () => groundGeometry?.dispose(), [groundGeometry])
 
   const handlers = useNodeEvents(node, 'site')
 
@@ -149,15 +163,14 @@ export const SiteRenderer = ({ node }: { node: SiteNode }) => {
       ))}
 
       {/* Ground fill: site polygon with slab holes, occludes below-grade geometry */}
-      {groundShape && (
+      {groundGeometry && (
         <mesh
+          geometry={groundGeometry}
           material={groundMaterial}
           position={[0, -0.05, 0]}
           receiveShadow
           rotation={[-Math.PI / 2, 0, 0]}
-        >
-          <shapeGeometry args={[groundShape]} />
-        </mesh>
+        />
       )}
 
       {/* Simple boundary line */}

packages/nodes/src/slab/boundary-editor.tsx

@@ -1,7 +1,12 @@
 'use client'
 
 import { resolveLevelId, type SlabNode, useLiveNodeOverrides, useScene } from '@pascal-app/core'
-import { PolygonEditor } from '@pascal-app/editor'
+import {
+  clearSlabSnapFeedback,
+  PolygonEditor,
+  type PolygonEditorPlanPointSnapContext,
+  resolveSlabPlanPointSnap,
+} from '@pascal-app/editor'
 import { useViewer } from '@pascal-app/viewer'
 import { useCallback, useEffect } from 'react'
 
@@ -30,9 +35,11 @@ export const SlabBoundaryEditor: React.FC<{ slabId: SlabNode['id'] }> = ({ slabI
   const setSelection = useViewer((s) => s.setSelection)
 
   const slab = slabNode?.type === 'slab' ? (slabNode as SlabNode) : null
+  const slabLevelId = slab ? resolveLevelId(slab, useScene.getState().nodes) : null
 
   const handlePolygonChange = useCallback(
     (newPolygon: Array<[number, number]>) => {
+      clearSlabSnapFeedback()
       updateNode(slabId, { polygon: newPolygon })
       setSelection({ selectedIds: [slabId] })
     },
@@ -46,6 +53,7 @@ export const SlabBoundaryEditor: React.FC<{ slabId: SlabNode['id'] }> = ({ slabI
           polygon: preview.map(([x, z]) => [x, z] as [number, number]),
         })
       } else {
+        clearSlabSnapFeedback()
         useLiveNodeOverrides.getState().clear(slabId)
       }
       markDirty(slabId)
@@ -53,11 +61,28 @@ export const SlabBoundaryEditor: React.FC<{ slabId: SlabNode['id'] }> = ({ slabI
     [slabId, markDirty],
   )
 
+  const handleDragCommit = useCallback(() => {
+    clearSlabSnapFeedback()
+  }, [])
+
+  const resolvePolygonEditorPlanPoint = useCallback(
+    (context: PolygonEditorPlanPointSnapContext) =>
+      resolveSlabPlanPointSnap({
+        rawPoint: context.rawPoint,
+        fallbackPoint: context.gridPoint,
+        levelId: slabLevelId,
+        excludeId: slabId,
+        altKey: context.nativeEvent?.altKey === true,
+      }).point,
+    [slabId, slabLevelId],
+  )
+
   // Guarantee the override clears if the editor unmounts mid-drag
   // (selection change, mode switch) so the slab mesh doesn't get stuck
   // on a stale polygon.
   useEffect(() => {
     return () => {
+      clearSlabSnapFeedback()
       useLiveNodeOverrides.getState().clear(slabId)
       useScene.getState().markDirty(slabId)
     }
@@ -69,11 +94,13 @@ export const SlabBoundaryEditor: React.FC<{ slabId: SlabNode['id'] }> = ({ slabI
     <PolygonEditor
       allowEdgeMove
       color="#a3a3a3"
-      levelId={resolveLevelId(slab, useScene.getState().nodes)}
+      levelId={slabLevelId ?? undefined}
       minVertices={3}
+      onDragCommit={handleDragCommit}
       onPolygonChange={handlePolygonChange}
       onPolygonPreview={handlePolygonPreview}
       polygon={slab.polygon}
+      resolvePlanPoint={resolvePolygonEditorPlanPoint}
       surfaceHeight={slab.elevation ?? 0.05}
     />
   )

packages/nodes/src/slab/floorplan-affordances.ts

@@ -1,8 +1,10 @@
-import type { SlabNode } from '@pascal-app/core'
+import { type AnyNode, resolveLevelId, type SlabNode } from '@pascal-app/core'
+import { resolveSlabPlanPointSnap } from '@pascal-app/editor'
 import {
   createPolygonAddVertexAffordance,
   createPolygonMoveEdgeAffordance,
   createPolygonVertexAffordance,
+  type PolygonAffordanceSnapContext,
 } from '../shared/polygon-vertex-affordance'
 
 /**
@@ -19,6 +21,35 @@ import {
  * the slab is selected, every hole's handles appear at the same time.
  * Simpler model, no UX downside in practice.
  */
-export const slabMoveVertexAffordance = createPolygonVertexAffordance<SlabNode>('slab')
-export const slabAddVertexAffordance = createPolygonAddVertexAffordance<SlabNode>('slab')
-export const slabMoveEdgeAffordance = createPolygonMoveEdgeAffordance<SlabNode>('slab')
+const slabSnapOptions = {
+  resolvePlanPoint({
+    node,
+    nodes,
+    rawPoint,
+    fallbackPoint,
+    modifiers,
+  }: PolygonAffordanceSnapContext<SlabNode>) {
+    const sceneNodes = nodes as Record<string, AnyNode>
+    return resolveSlabPlanPointSnap({
+      rawPoint,
+      fallbackPoint,
+      levelId: resolveLevelId(node, sceneNodes),
+      excludeId: node.id,
+      nodes: sceneNodes,
+      altKey: modifiers.altKey,
+    }).point
+  },
+}
+
+export const slabMoveVertexAffordance = createPolygonVertexAffordance<SlabNode>(
+  'slab',
+  slabSnapOptions,
+)
+export const slabAddVertexAffordance = createPolygonAddVertexAffordance<SlabNode>(
+  'slab',
+  slabSnapOptions,
+)
+export const slabMoveEdgeAffordance = createPolygonMoveEdgeAffordance<SlabNode>(
+  'slab',
+  slabSnapOptions,
+)

packages/nodes/src/slab/tool.tsx

@@ -1,19 +1,13 @@
 'use client'
 
-import {
-  collectAlignmentAnchors,
-  emitter,
-  type GridEvent,
-  type LevelNode,
-  resolveAlignment,
-  useScene,
-} from '@pascal-app/core'
+import { emitter, type GridEvent, type LevelNode, useScene } from '@pascal-app/core'
 import {
   CursorSphere,
+  clearSlabSnapFeedback,
   EDITOR_LAYER,
   markToolCancelConsumed,
+  resolveSlabPlanPointSnap,
   triggerSFX,
-  useAlignmentGuides,
   useEditor,
 } from '@pascal-app/editor'
 import { useViewer } from '@pascal-app/viewer'
@@ -34,8 +28,6 @@ import { SlabNode } from './schema'
  */
 
 const Y_OFFSET = 0.02
-/** Figma-style alignment-snap threshold (meters), matching the move tools. */
-const ALIGNMENT_THRESHOLD_M = 0.08
 
 function calculateSnapPoint(
   lastPoint: [number, number],
@@ -90,52 +82,11 @@ export const SlabTool: React.FC = () => {
   // isn't built with a stale preset's parameters. Unmount-only.
   useEffect(() => () => useEditor.getState().setToolDefaults('slab', null), [])
 
-  // Clear alignment guides on unmount ONLY. The main drawing effect re-runs
-  // on every cursor move (cursorPosition is in its deps), so clearing guides
-  // in its cleanup would wipe the guide the instant after each move sets it.
-  useEffect(() => () => useAlignmentGuides.getState().clear(), [])
+  useEffect(() => () => clearSlabSnapFeedback(), [])
 
   useEffect(() => {
     if (!currentLevelId) return
 
-    // Alignment candidates — anchors of every OTHER alignable object. The
-    // slab's own in-progress vertices are intentionally excluded (no
-    // self-alignment while drawing).
-    const alignmentCandidates = collectAlignmentAnchors(useScene.getState().nodes, '')
-    // Snap the drafted vertex onto another object's nearest real anchor and
-    // publish the guide. The probe is the RAW cursor, NOT the 0.5m-grid-snapped
-    // point: resolving against the grid point would only ever catch anchors
-    // that happen to sit on a grid line, so off-grid items (furniture, angled
-    // walls) would never surface a guide. The matched axis locks exactly to the
-    // candidate's coordinate; the other axis keeps its grid/ortho snap. Alt
-    // bypasses.
-    const alignPoint = (
-      fallback: [number, number],
-      raw: [number, number],
-      bypass: boolean,
-    ): [number, number] => {
-      if (bypass || alignmentCandidates.length === 0) {
-        useAlignmentGuides.getState().clear()
-        return fallback
-      }
-      const ar = resolveAlignment({
-        moving: [{ nodeId: '__slab-draft__', kind: 'corner', x: raw[0], z: raw[1] }],
-        candidates: alignmentCandidates,
-        threshold: ALIGNMENT_THRESHOLD_M,
-      })
-      if (ar.guides.length === 0) {
-        useAlignmentGuides.getState().clear()
-        return fallback
-      }
-      useAlignmentGuides.getState().set(ar.guides)
-      let [x, z] = fallback
-      for (const guide of ar.guides) {
-        if (guide.axis === 'x') x = guide.coord
-        else z = guide.coord
-      }
-      return [x, z]
-    }
-
     const onGridMove = (event: GridEvent) => {
       if (!cursorRef.current) return
       const rawPoint: [number, number] = [event.localPosition[0], event.localPosition[2]]
@@ -149,7 +100,12 @@ export const SlabTool: React.FC = () => {
         shiftPressed.current || !lastPoint
           ? gridPosition
           : calculateSnapPoint(lastPoint, gridPosition)
-      const displayPoint = alignPoint(orthoPoint, rawPoint, event.nativeEvent?.altKey === true)
+      const displayPoint = resolveSlabPlanPointSnap({
+        rawPoint,
+        fallbackPoint: orthoPoint,
+        levelId: currentLevelId,
+        altKey: event.nativeEvent?.altKey === true,
+      }).point
       setSnappedCursorPosition(displayPoint)
       if (
         points.length > 0 &&
@@ -176,7 +132,7 @@ export const SlabTool: React.FC = () => {
         const slabId = commitSlabDrawing(currentLevelId, points)
         setSelection({ selectedIds: [slabId] })
         setPoints([])
-        useAlignmentGuides.getState().clear()
+        clearSlabSnapFeedback()
       } else {
         // Every non-closing vertex is a "start" tick; the closing click above
         // fires the structure-build (end) cue.
@@ -191,14 +147,14 @@ export const SlabTool: React.FC = () => {
         const slabId = commitSlabDrawing(currentLevelId, points)
         setSelection({ selectedIds: [slabId] })
         setPoints([])
-        useAlignmentGuides.getState().clear()
+        clearSlabSnapFeedback()
       }
     }
 
     const onCancel = () => {
       if (points.length > 0) markToolCancelConsumed()
       setPoints([])
-      useAlignmentGuides.getState().clear()
+      clearSlabSnapFeedback()
     }
 
     const onKeyDown = (e: KeyboardEvent) => {

packages/nodes/src/spawn/__tests__/parity.test.ts

@@ -31,6 +31,7 @@ describe('spawn definition', () => {
     expect(spawnDefinition.schemaVersion).toBe(1)
     expect(spawnDefinition.category).toBe('site')
     expect(spawnDefinition.schema).toBe(SpawnNode)
+    expect(typeof spawnDefinition.floorplanMoveTarget).toBe('function')
   })
 
   test('defaults() returns a value that the schema accepts', () => {
@@ -111,6 +112,7 @@ describe('spawn definition', () => {
 
     const flat = flattenFloorplan(geometry)
     expect(flat.some((entry) => entry.kind === 'path' && entry.stroke === '#818cf8')).toBe(true)
+    expect(flat.some((entry) => entry.kind === 'move-handle')).toBe(true)
     expect(flat.some((entry) => entry.kind === 'rotate-arrow')).toBe(true)
   })
 

packages/nodes/src/spawn/definition.ts

@@ -1,6 +1,7 @@
 import type { HandleDescriptor, NodeDefinition, SpawnNode as SpawnNodeType } from '@pascal-app/core'
 import { buildSpawnFloorplan } from './floorplan'
 import { spawnRotateAffordance } from './floorplan-affordances'
+import { spawnFloorplanMoveTarget } from './floorplan-move'
 import { spawnParametrics } from './parametrics'
 import { SpawnNode } from './schema'
 
@@ -92,6 +93,7 @@ export const spawnDefinition: NodeDefinition<typeof SpawnNode> = {
   // delete. Legacy spawn click handlers in FloorplanNodeLayer become
   // dead code once Phase 6 cleanup removes the [] entries path.
   floorplan: buildSpawnFloorplan,
+  floorplanMoveTarget: spawnFloorplanMoveTarget,
   floorplanAffordances: {
     'spawn-rotate': spawnRotateAffordance,
   },

packages/nodes/src/spawn/floorplan-move.ts

@@ -0,0 +1,39 @@
+import {
+  type AnyNodeId,
+  type FloorplanMoveTarget,
+  type FloorplanMoveTargetSession,
+  type SpawnNode,
+  snapScalar,
+  useScene,
+} from '@pascal-app/core'
+import { getSegmentGridStep } from '@pascal-app/editor'
+
+export const spawnFloorplanMoveTarget: FloorplanMoveTarget<SpawnNode> = ({ node }) => {
+  const spawnId = node.id as AnyNodeId
+  const startY = node.position[1]
+  const originalPosition: [number, number, number] = [...node.position]
+  let lastPosition: [number, number, number] | null = null
+
+  const session: FloorplanMoveTargetSession = {
+    affectedIds: [spawnId],
+    apply({ planPoint, modifiers }) {
+      const step = getSegmentGridStep()
+      const snap = (value: number) => (modifiers.shiftKey ? value : snapScalar(value, step))
+      const next: [number, number, number] = [snap(planPoint[0]), startY, snap(planPoint[1])]
+
+      if (lastPosition && lastPosition[0] === next[0] && lastPosition[2] === next[2]) return
+      lastPosition = next
+      useScene.getState().updateNodes([{ id: spawnId, data: { position: next } }])
+    },
+    canCommit() {
+      if (!lastPosition) return false
+      return lastPosition[0] !== originalPosition[0] || lastPosition[2] !== originalPosition[2]
+    },
+    commit() {
+      if (!lastPosition) return
+      useScene.getState().updateNodes([{ id: spawnId, data: { position: lastPosition } }])
+    },
+  }
+
+  return session
+}

packages/nodes/src/spawn/floorplan.ts

@@ -113,6 +113,11 @@ export function buildSpawnFloorplan(node: SpawnNode, ctx: GeometryContext): Floo
   ]
 
   if (isSelected) {
+    children.push({
+      kind: 'move-handle',
+      point: [px, pz],
+    })
+
     const cornerLocalX = 0.34 + ROTATE_ARROW_CORNER_OFFSET
     const cornerLocalZ = 0.34 + ROTATE_ARROW_CORNER_OFFSET
     const [cornerX, cornerZ] = rotatePlanVector(cornerLocalX, cornerLocalZ, planRotation)

packages/nodes/src/window/definition.ts

@@ -2,9 +2,12 @@ import type {
   AnyNodeId,
   HandleDescriptor,
   NodeDefinition,
+  RoofSegmentNode,
   WallNode,
   WindowNode as WindowNodeType,
 } from '@pascal-app/core'
+import { readRoofFaceHeightMax, readRoofFaceWidthMax } from '../shared/roof-opening-host'
+import { buildRoofWallOpeningCut } from '../shared/roof-wall-opening-cut'
 import { buildWindowFloorplan } from './floorplan'
 import { windowWidthAffordance } from './floorplan-affordances'
 import { windowFloorplanMoveTarget } from './floorplan-move'
@@ -36,7 +39,13 @@ function windowWidthHandle(side: 'left' | 'right'): HandleDescriptor<WindowNodeT
     axis: 'x',
     anchor: side === 'right' ? 'min' : 'max',
     min: MIN_WINDOW_WIDTH,
-    max: (n, scene) => readWallLength(n, scene),
+    max: (n, scene) => {
+      // Roof-hosted windows clamp against the face profile (the
+      // wall-based limits read Infinity when wallId is unset).
+      const roofMax = readRoofFaceWidthMax(n, scene, sign)
+      if (roofMax !== null) return Math.max(MIN_WINDOW_WIDTH, roofMax)
+      return readWallLength(n, scene)
+    },
     currentValue: (n) => n.width,
     apply: (initial, newWidth) => {
       const rotY = initial.rotation[1]
@@ -73,6 +82,8 @@ function windowHeightHandle(edge: 'top' | 'bottom'): HandleDescriptor<WindowNode
     anchor: edge === 'top' ? 'min' : 'max',
     min: MIN_WINDOW_HEIGHT,
     max: (n, scene) => {
+      const roofMax = readRoofFaceHeightMax(n, scene, sign)
+      if (roofMax !== null) return Math.max(MIN_WINDOW_HEIGHT, roofMax)
       // Maximum: distance from the anchored edge to the wall's allowed Y
       // bounds. Top arrow caps at wall.height - bottom; bottom arrow caps
       // at top (positive Y room above the floor).
@@ -139,9 +150,18 @@ export const windowDefinition: NodeDefinition<typeof WindowNode> = {
     duplicable: true,
     deletable: true,
     wallOpeningPlacement: true,
-    // `wallId` is re-derived from the wall under the cursor at preset
-    // placement time — see the door capability for the same pattern.
-    hostRefFields: ['wallId'],
+    // Windows also host on roof-segment wall faces (base walls under the
+    // roof, gable ends) — same wiring as door; see the door capability
+    // for why `dirtyHandledByOwnSystem` is required.
+    roofAccessory: {
+      buildCut: (node, hostSegment) =>
+        buildRoofWallOpeningCut(node as WindowNodeType, hostSegment as RoofSegmentNode),
+      cutScope: 'wall',
+      dirtyHandledByOwnSystem: true,
+    },
+    // `wallId` / `roofSegmentId` are re-derived from the surface under
+    // the cursor at preset placement time — see door for the pattern.
+    hostRefFields: ['wallId', 'roofSegmentId', 'roofFace'],
   },
 
   parametrics: windowParametrics,

packages/nodes/src/window/floorplan-move.ts

@@ -8,6 +8,10 @@ import {
 } from '@pascal-app/core'
 import { snapToHalf } from '@pascal-app/editor'
 import { createFloorplanCursorResolver } from '../shared/floorplan-cursor'
+import {
+  getRoofHostedOpeningLevelId,
+  getRoofHostedOpeningPlanPoint,
+} from '../shared/roof-opening-host'
 import {
   findClosestWallInPlan,
   projectWallLocalPointToPlan,
@@ -29,7 +33,12 @@ import { clampToWall, hasWallChildOverlap } from './window-math'
 
 export const windowFloorplanMoveTarget: FloorplanMoveTarget<WindowNode> = ({ node }) => {
   const startLevelId = (() => {
-    const wall = useScene.getState().nodes[node.parentId as AnyNodeId]
+    // Wall-hosted: the wall's parent is the level. Roof-hosted: walk
+    // segment → roof → level.
+    const nodes = useScene.getState().nodes
+    const roofLevelId = getRoofHostedOpeningLevelId(node, nodes)
+    if (roofLevelId) return roofLevelId
+    const wall = nodes[node.parentId as AnyNodeId]
     return wall ? (wall.parentId as AnyNodeId | null) : null
   })()
   const originalWall = node.parentId
@@ -39,7 +48,7 @@ export const windowFloorplanMoveTarget: FloorplanMoveTarget<WindowNode> = ({ nod
     original:
       originalWall?.type === 'wall'
         ? projectWallLocalPointToPlan(originalWall, node.position[0])
-        : [node.position[0], 0],
+        : (getRoofHostedOpeningPlanPoint(node, useScene.getState().nodes) ?? [node.position[0], 0]),
     metadata: node.metadata,
   })
 
@@ -56,6 +65,8 @@ export const windowFloorplanMoveTarget: FloorplanMoveTarget<WindowNode> = ({ nod
     side: WindowNode['side']
     parentId: string
     wallId: string
+    roofSegmentId: undefined
+    roofFace: undefined
   } | null = null
 
   const session: FloorplanMoveTargetSession = {
@@ -93,6 +104,10 @@ export const windowFloorplanMoveTarget: FloorplanMoveTarget<WindowNode> = ({ nod
         side: hit.side,
         parentId: hit.wall.id,
         wallId: hit.wall.id,
+        // Re-anchoring to a wall ends any roof-segment hosting; the
+        // overlay's snapshot restores it if the move is reverted.
+        roofSegmentId: undefined,
+        roofFace: undefined,
       }
 
       useScene.getState().updateNodes([

packages/nodes/src/window/move-tool.tsx

@@ -3,6 +3,8 @@ import {
   collectAlignmentAnchors,
   emitter,
   isCurvedWall,
+  type RoofEvent,
+  type RoofNode,
   sceneRegistry,
   spatialGridManager,
   useLiveTransforms,
@@ -17,6 +19,7 @@ import {
   getSideFromNormal,
   isValidWallSideFace,
   snapToHalf,
+  stripPlacementMetadataFlags,
   triggerSFX,
   useAlignmentGuides,
   useEditor,
@@ -25,6 +28,11 @@ import { useViewer } from '@pascal-app/viewer'
 import { useCallback, useEffect, useMemo, useRef } from 'react'
 import { BoxGeometry, EdgesGeometry, type Group } from 'three'
 import { LineBasicNodeMaterial } from 'three/webgpu'
+import {
+  getRoofWallOpeningCursorPose,
+  type RoofWallOpeningTarget,
+  resolveRoofWallOpeningTarget,
+} from '../shared/roof-wall-opening-placement'
 import { resolveWallSlideAlignment } from '../shared/wall-opening-alignment'
 import { clampToWall, hasWallChildOverlap, wallLocalToWorld } from './window-math'
 
@@ -70,6 +78,11 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
       side: movingWindowNode.side,
       parentId: movingWindowNode.parentId,
       wallId: movingWindowNode.wallId,
+      // Windows can be hosted on a roof-segment wall face. Moving onto a
+      // wall re-anchors as wall-hosted (roofSegmentId cleared); reverts
+      // must restore the roof host.
+      roofSegmentId: movingWindowNode.roofSegmentId,
+      roofFace: movingWindowNode.roofFace,
       metadata: movingWindowNode.metadata,
     }
 
@@ -85,7 +98,7 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
       })
     }
 
-    let currentWallId: string | null = movingWindowNode.parentId
+    let currentHostId: string | null = movingWindowNode.parentId
     let dragAnchor: {
       wallId: string
       rawX: number
@@ -105,18 +118,18 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
       event: WallEvent
     } | null = null
 
-    const markWallDirty = (wallId: string | null) => {
-      if (wallId) useScene.getState().dirtyNodes.add(wallId as AnyNodeId)
+    const markHostDirty = (hostId: string | null) => {
+      if (hostId) useScene.getState().dirtyNodes.add(hostId as AnyNodeId)
     }
-    const lastWallDirtyAt = new Map<string, number>()
-    const markWallDirtyThrottled = (wallId: string | null) => {
-      if (!wallId) return
+    const lastHostDirtyAt = new Map<string, number>()
+    const markHostDirtyThrottled = (hostId: string | null) => {
+      if (!hostId) return
       const now = globalThis.performance?.now?.() ?? Date.now()
-      const last = lastWallDirtyAt.get(wallId) ?? 0
+      const last = lastHostDirtyAt.get(hostId) ?? 0
       // Wall rebuilds can trigger expensive CSG; throttle live previews to avoid FPS collapse.
       if (now - last > 120) {
-        lastWallDirtyAt.set(wallId, now)
-        markWallDirty(wallId)
+        lastHostDirtyAt.set(hostId, now)
+        markHostDirty(hostId)
       }
     }
 
@@ -223,16 +236,18 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
     }
 
     const applyPreview = (target: NonNullable<typeof lastTarget>) => {
-      if (currentWallId !== target.wallId) {
+      if (currentHostId !== target.wallId) {
         useScene.getState().updateNode(movingWindowNode.id, {
           position: [target.clampedX, target.clampedY, 0],
           rotation: [0, target.itemRotation, 0],
           side: target.side,
           parentId: target.wallId,
           wallId: target.wallId,
+          roofSegmentId: undefined,
+          roofFace: undefined,
         })
-        markWallDirty(currentWallId)
-        currentWallId = target.wallId
+        markHostDirty(currentHostId)
+        currentHostId = target.wallId
       } else {
         const windowMesh = sceneRegistry.nodes.get(movingWindowNode.id as AnyNodeId)
         if (windowMesh) {
@@ -245,7 +260,7 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
         position: [target.clampedX, target.clampedY, 0],
         rotation: target.itemRotation,
       })
-      markWallDirtyThrottled(target.wallId)
+      markHostDirtyThrottled(target.wallId)
 
       updateCursor(
         wallLocalToWorld(
@@ -303,10 +318,7 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
 
         const cloned = structuredClone(movingWindowNode) as any
         delete cloned.id
-        if (cloned.metadata && typeof cloned.metadata === 'object') {
-          delete cloned.metadata.isNew
-          delete cloned.metadata.isTransient
-        }
+        cloned.metadata = stripPlacementMetadataFlags(cloned.metadata)
 
         const node = WindowNode.parse({
           ...cloned,
@@ -315,6 +327,8 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
           side: target.side,
           wallId: target.wallId,
           parentId: target.wallId,
+          roofSegmentId: undefined,
+          roofFace: undefined,
         })
         useScene.getState().createNode(node, target.wallId as AnyNodeId)
         placedId = node.id
@@ -327,6 +341,8 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
           side: original.side,
           parentId: original.parentId,
           wallId: original.wallId,
+          roofSegmentId: original.roofSegmentId,
+          roofFace: original.roofFace,
           metadata: original.metadata,
         })
         useScene.temporal.getState().resume()
@@ -337,16 +353,17 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
           side: target.side,
           parentId: target.wallId,
           wallId: target.wallId,
+          roofSegmentId: undefined,
           metadata: {},
         })
 
         if (original.parentId && original.parentId !== target.wallId) {
-          markWallDirty(original.parentId)
+          markHostDirty(original.parentId)
         }
         placedId = movingWindowNode.id
       }
 
-      markWallDirty(target.wallId)
+      markHostDirty(target.wallId)
       useLiveTransforms.getState().clear(movingWindowNode.id)
       useScene.temporal.getState().pause()
 
@@ -364,25 +381,99 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
       lastTarget = null
       if (isNew) return // No original to restore for duplicates
       // Move mode: restore to original position while off-wall
-      if (currentWallId && currentWallId !== original.parentId) {
-        markWallDirty(currentWallId)
+      if (currentHostId && currentHostId !== original.parentId) {
+        markHostDirty(currentHostId)
       }
-      currentWallId = original.parentId
+      currentHostId = original.parentId
       useScene.getState().updateNode(movingWindowNode.id, {
         position: original.position,
         rotation: original.rotation,
         side: original.side,
         parentId: original.parentId,
         wallId: original.wallId,
+        roofSegmentId: original.roofSegmentId,
+        roofFace: original.roofFace,
       })
-      if (original.parentId) markWallDirty(original.parentId)
+      if (original.parentId) markHostDirty(original.parentId)
     }
 
-    const onCancel = () => {
+    // ── Roof-segment wall faces ─────────────────────────────────────
+    // Mirrors the wall flow for the segments' vertical wall faces (base
+    // walls under the roof + coplanar gable ends — a window can sit in
+    // the gable pediment). This is also the placement path preset tiles
+    // take (`metadata.isNew` clones).
+
+    const resolveRoofMoveTarget = (event: RoofEvent) =>
+      resolveRoofWallOpeningTarget({
+        event,
+        width: movingWindowNode.width,
+        height: movingWindowNode.height,
+        ignoreId: movingWindowNode.id,
+        vertical: { kind: 'free', snap: snapToHalf },
+      })
+
+    const updateRoofCursor = (target: RoofWallOpeningTarget, roof: RoofNode) => {
+      const pose = getRoofWallOpeningCursorPose(target, roof)
+      if (pose) updateCursor(pose.position, pose.rotationY, target.valid)
+    }
+
+    const onRoofHover = (event: RoofEvent) => {
+      const target = resolveRoofMoveTarget(event)
+      if (!target) return
+      // Wall-frame drag anchor / live transform don't apply on a roof face.
+      dragAnchor = null
+      lastTarget = null
       useLiveTransforms.getState().clear(movingWindowNode.id)
+      if (currentHostId !== target.segment.id) {
+        useScene.getState().updateNode(movingWindowNode.id, {
+          position: target.position,
+          rotation: [0, 0, 0],
+          side: 'front',
+          parentId: target.segment.id,
+          wallId: undefined,
+          roofSegmentId: target.segment.id,
+          roofFace: target.face.id,
+        })
+        markHostDirty(currentHostId)
+        currentHostId = target.segment.id
+      } else {
+        useScene.getState().updateNode(movingWindowNode.id, {
+          position: target.position,
+          rotation: [0, 0, 0],
+          roofFace: target.face.id,
+        })
+      }
+      updateRoofCursor(target, event.node as RoofNode)
+      event.stopPropagation()
+    }
+
+    const onRoofClick = (event: RoofEvent) => {
+      const target = resolveRoofMoveTarget(event)
+      if (!target?.valid) return
+      const segmentId = target.segment.id
+
+      let placedId: string
+
       if (isNew) {
         useScene.getState().deleteNode(movingWindowNode.id)
-        if (currentWallId) markWallDirty(currentWallId)
+        useScene.temporal.getState().resume()
+
+        const cloned = structuredClone(movingWindowNode) as any
+        delete cloned.id
+        cloned.metadata = stripPlacementMetadataFlags(cloned.metadata)
+
+        const node = WindowNode.parse({
+          ...cloned,
+          position: target.position,
+          rotation: [0, 0, 0],
+          side: 'front',
+          wallId: undefined,
+          roofSegmentId: segmentId,
+          roofFace: target.face.id,
+          parentId: segmentId,
+        })
+        useScene.getState().createNode(node, segmentId as AnyNodeId)
+        placedId = node.id
       } else {
         useScene.getState().updateNode(movingWindowNode.id, {
           position: original.position,
@@ -390,9 +481,79 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
           side: original.side,
           parentId: original.parentId,
           wallId: original.wallId,
+          roofSegmentId: original.roofSegmentId,
+          roofFace: original.roofFace,
           metadata: original.metadata,
         })
-        if (original.parentId) markWallDirty(original.parentId)
+        useScene.temporal.getState().resume()
+
+        useScene.getState().updateNode(movingWindowNode.id, {
+          position: target.position,
+          rotation: [0, 0, 0],
+          side: 'front',
+          parentId: segmentId,
+          wallId: undefined,
+          roofSegmentId: segmentId,
+          roofFace: target.face.id,
+          metadata: {},
+        })
+
+        if (original.parentId && original.parentId !== segmentId) {
+          markHostDirty(original.parentId)
+        }
+        placedId = movingWindowNode.id
+      }
+
+      markHostDirty(segmentId)
+      useLiveTransforms.getState().clear(movingWindowNode.id)
+      useScene.temporal.getState().pause()
+
+      triggerSFX('sfx:structure-build')
+      hideCursor()
+      useViewer.getState().setSelection({ selectedIds: [placedId] })
+      exitMoveMode()
+      event.stopPropagation()
+    }
+
+    const onRoofLeave = () => {
+      hideCursor()
+      useLiveTransforms.getState().clear(movingWindowNode.id)
+      dragAnchor = null
+      lastTarget = null
+      if (isNew) return
+      if (currentHostId && currentHostId !== original.parentId) {
+        markHostDirty(currentHostId)
+      }
+      currentHostId = original.parentId
+      useScene.getState().updateNode(movingWindowNode.id, {
+        position: original.position,
+        rotation: original.rotation,
+        side: original.side,
+        parentId: original.parentId,
+        wallId: original.wallId,
+        roofSegmentId: original.roofSegmentId,
+        roofFace: original.roofFace,
+      })
+      if (original.parentId) markHostDirty(original.parentId)
+    }
+
+    const onCancel = () => {
+      useLiveTransforms.getState().clear(movingWindowNode.id)
+      if (isNew) {
+        useScene.getState().deleteNode(movingWindowNode.id)
+        if (currentHostId) markHostDirty(currentHostId)
+      } else {
+        useScene.getState().updateNode(movingWindowNode.id, {
+          position: original.position,
+          rotation: original.rotation,
+          side: original.side,
+          parentId: original.parentId,
+          wallId: original.wallId,
+          roofSegmentId: original.roofSegmentId,
+          roofFace: original.roofFace,
+          metadata: original.metadata,
+        })
+        if (original.parentId) markHostDirty(original.parentId)
       }
       useScene.temporal.getState().resume()
       hideCursor()
@@ -403,6 +564,10 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
     emitter.on('wall:move', onWallMove)
     emitter.on('wall:click', onWallClick)
     emitter.on('wall:leave', onWallLeave)
+    emitter.on('roof:enter', onRoofHover)
+    emitter.on('roof:move', onRoofHover)
+    emitter.on('roof:click', onRoofClick)
+    emitter.on('roof:leave', onRoofLeave)
     emitter.on('tool:cancel', onCancel)
 
     return () => {
@@ -414,7 +579,7 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
       if (currentMeta?.isTransient) {
         if (isNew) {
           useScene.getState().deleteNode(movingWindowNode.id)
-          if (currentWallId) markWallDirty(currentWallId)
+          if (currentHostId) markHostDirty(currentHostId)
         } else {
           useScene.getState().updateNode(movingWindowNode.id, {
             position: original.position,
@@ -422,9 +587,11 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
             side: original.side,
             parentId: original.parentId,
             wallId: original.wallId,
+            roofSegmentId: original.roofSegmentId,
+            roofFace: original.roofFace,
             metadata: original.metadata,
           })
-          if (original.parentId) markWallDirty(original.parentId)
+          if (original.parentId) markHostDirty(original.parentId)
         }
       }
       useLiveTransforms.getState().clear(movingWindowNode.id)
@@ -434,6 +601,10 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
       emitter.off('wall:move', onWallMove)
       emitter.off('wall:click', onWallClick)
       emitter.off('wall:leave', onWallLeave)
+      emitter.off('roof:enter', onRoofHover)
+      emitter.off('roof:move', onRoofHover)
+      emitter.off('roof:click', onRoofClick)
+      emitter.off('roof:leave', onRoofLeave)
       emitter.off('tool:cancel', onCancel)
     }
   }, [movingWindowNode, exitMoveMode])

packages/nodes/src/window/panel.tsx

@@ -215,6 +215,8 @@ export default function WindowPanel() {
       rotation: [...node.rotation] as [number, number, number],
       side: node.side,
       wallId: node.wallId,
+      roofSegmentId: node.roofSegmentId,
+      roofFace: node.roofFace,
       parentId: node.parentId,
       width: node.width,
       height: node.height,

packages/nodes/src/window/renderer.tsx

@@ -9,6 +9,7 @@ import {
 } from '@pascal-app/viewer'
 import { useLayoutEffect, useMemo, useRef } from 'react'
 import type { Mesh } from 'three'
+import { RoofFaceHostFrame } from '../shared/roof-face-host'
 
 export const WindowRenderer = ({ node }: { node: WindowNode }) => {
   const ref = useRef<Mesh>(null!)
@@ -33,7 +34,7 @@ export const WindowRenderer = ({ node }: { node: WindowNode }) => {
     node.material?.texture,
   ])
 
-  return (
+  const mesh = (
     <mesh
       material={material}
       position={node.position}
@@ -45,6 +46,13 @@ export const WindowRenderer = ({ node }: { node: WindowNode }) => {
       <boxGeometry args={[0, 0, 0]} />
     </mesh>
   )
+
+  if (!node.roofSegmentId) return mesh
+  return (
+    <RoofFaceHostFrame roofFace={node.roofFace} roofSegmentId={node.roofSegmentId}>
+      {mesh}
+    </RoofFaceHostFrame>
+  )
 }
 
 export default WindowRenderer

packages/nodes/src/window/tool.tsx

@@ -3,6 +3,8 @@ import {
   collectAlignmentAnchors,
   emitter,
   isCurvedWall,
+  type RoofEvent,
+  type RoofNode,
   sceneRegistry,
   spatialGridManager,
   useScene,
@@ -23,6 +25,11 @@ import { useViewer } from '@pascal-app/viewer'
 import { useEffect, useRef } from 'react'
 import { BoxGeometry, EdgesGeometry, type Group, type LineSegments } from 'three'
 import { LineBasicNodeMaterial } from 'three/webgpu'
+import {
+  getRoofWallOpeningCursorPose,
+  type RoofWallOpeningTarget,
+  resolveRoofWallOpeningTarget,
+} from '../shared/roof-wall-opening-placement'
 import { resolveWallSlideAlignment } from '../shared/wall-opening-alignment'
 import { clampToWall, hasWallChildOverlap, wallLocalToWorld } from './window-math'
 
@@ -35,7 +42,9 @@ const edgeMaterial = new LineBasicNodeMaterial({
 })
 
 /**
- * Window tool — places WindowNodes on walls only.
+ * Window tool — places WindowNodes on walls and on roof-segment wall
+ * faces (the generated base walls under a roof, including coplanar gable
+ * ends — a window can sit in the gable pediment).
  * Shows a rectangle cursor (green = valid, red = invalid) matching window dimensions.
  */
 const WindowTool: React.FC = () => {
@@ -58,8 +67,8 @@ const WindowTool: React.FC = () => {
         wallEvent.node.end,
       )
 
-    const markWallDirty = (wallId: string) => {
-      useScene.getState().dirtyNodes.add(wallId as AnyNodeId)
+    const markHostDirty = (hostId: string) => {
+      useScene.getState().dirtyNodes.add(hostId as AnyNodeId)
     }
 
     const destroyDraft = () => {
@@ -68,7 +77,7 @@ const WindowTool: React.FC = () => {
       useScene.getState().deleteNode(draftRef.current.id)
       draftRef.current = null
       // Rebuild wall so it removes the cutout from the deleted draft
-      if (wallId) markWallDirty(wallId)
+      if (wallId) markHostDirty(wallId)
     }
 
     const hideCursor = () => {
@@ -215,7 +224,7 @@ const WindowTool: React.FC = () => {
             rotation: [0, itemRotation, 0],
             side,
           })
-          markWallDirty(event.node.id)
+          markHostDirty(event.node.id)
         } else {
           useScene.getState().updateNode(draftRef.current.id, {
             position: [clampedX, clampedY, 0],
@@ -223,6 +232,9 @@ const WindowTool: React.FC = () => {
             side,
             parentId: event.node.id,
             wallId: event.node.id,
+            // The draft may arrive from a roof-segment face hover.
+            roofSegmentId: undefined,
+            roofFace: undefined,
           })
         }
       }
@@ -343,6 +355,122 @@ const WindowTool: React.FC = () => {
       hideCursor()
     }
 
+    // ── Roof-segment wall faces ─────────────────────────────────────
+    // The merged roof mesh emits `roof:*`; hits are resolved against the
+    // segments' vertical wall faces (base walls + coplanar gable ends),
+    // so a window can sit anywhere inside the face profile — including
+    // the gable pediment triangle.
+
+    const resolveRoofTarget = (event: RoofEvent) =>
+      resolveRoofWallOpeningTarget({
+        event,
+        width: draftRef.current?.width ?? 1.5,
+        height: draftRef.current?.height ?? 1.5,
+        ignoreId: draftRef.current?.id,
+        vertical: { kind: 'free', snap: snapToHalf },
+      })
+
+    const updateRoofCursor = (target: RoofWallOpeningTarget, roof: RoofNode) => {
+      const pose = getRoofWallOpeningCursorPose(target, roof)
+      if (pose) updateCursor(pose.position, pose.rotationY, target.valid)
+    }
+
+    const onRoofHover = (event: RoofEvent) => {
+      const target = resolveRoofTarget(event)
+      if (!target) {
+        // On the roof but not over a placeable wall face (slope, soffit,
+        // or a face the window cannot fit on).
+        if (draftRef.current?.roofSegmentId) {
+          destroyDraft()
+          hideCursor()
+        }
+        return
+      }
+      const { segment, face, position } = target
+
+      if (draftRef.current && draftRef.current.parentId !== segment.id) destroyDraft()
+      if (draftRef.current) {
+        useScene.getState().updateNode(draftRef.current.id, {
+          position,
+          rotation: [0, 0, 0],
+          roofFace: face.id,
+        })
+      } else {
+        const node = WindowNode.parse({
+          position,
+          rotation: [0, 0, 0],
+          side: 'front',
+          roofSegmentId: segment.id,
+          roofFace: face.id,
+          parentId: segment.id,
+          metadata: { isTransient: true },
+        })
+        useScene.getState().createNode(node, segment.id as AnyNodeId)
+        draftRef.current = node
+      }
+      updateRoofCursor(target, event.node as RoofNode)
+      event.stopPropagation()
+    }
+
+    const onRoofClick = (event: RoofEvent) => {
+      if (!draftRef.current?.roofSegmentId) return
+      const target = resolveRoofTarget(event)
+      if (!target?.valid) return
+      const { segment, face, position } = target
+
+      const draft = draftRef.current
+      draftRef.current = null
+
+      useScene.getState().deleteNode(draft.id)
+      useScene.temporal.getState().resume()
+
+      const state = useScene.getState()
+      const windowCount = Object.values(state.nodes).filter(
+        (n) => n.type === 'window' && (n as WindowNode).roofSegmentId !== undefined,
+      ).length
+
+      const node = WindowNode.parse({
+        name: `Window ${windowCount + 1}`,
+        position,
+        rotation: [0, 0, 0],
+        side: 'front',
+        roofSegmentId: segment.id,
+        roofFace: face.id,
+        parentId: segment.id,
+        width: draft.width,
+        height: draft.height,
+        windowType: draft.windowType,
+        operationState: draft.operationState,
+        awningDirection: draft.awningDirection,
+        casementStyle: draft.casementStyle,
+        hingesSide: draft.hingesSide,
+        frameThickness: draft.frameThickness,
+        frameDepth: draft.frameDepth,
+        columnRatios: draft.columnRatios,
+        rowRatios: draft.rowRatios,
+        columnDividerThickness: draft.columnDividerThickness,
+        rowDividerThickness: draft.rowDividerThickness,
+        sill: draft.sill,
+        sillDepth: draft.sillDepth,
+        sillThickness: draft.sillThickness,
+      })
+
+      useScene.getState().createNode(node, segment.id as AnyNodeId)
+      // Rebuild the segment (and the merged roof) so the wall brush
+      // picks up the new opening cut.
+      useScene.getState().dirtyNodes.add(segment.id as AnyNodeId)
+      useViewer.getState().setSelection({ selectedIds: [node.id] })
+      useScene.temporal.getState().pause()
+      triggerSFX('sfx:structure-build')
+      event.stopPropagation()
+    }
+
+    const onRoofLeave = () => {
+      if (!draftRef.current?.roofSegmentId) return
+      destroyDraft()
+      hideCursor()
+    }
+
     const onCancel = () => {
       destroyDraft()
       hideCursor()
@@ -352,6 +480,10 @@ const WindowTool: React.FC = () => {
     emitter.on('wall:move', onWallMove)
     emitter.on('wall:click', onWallClick)
     emitter.on('wall:leave', onWallLeave)
+    emitter.on('roof:enter', onRoofHover)
+    emitter.on('roof:move', onRoofHover)
+    emitter.on('roof:click', onRoofClick)
+    emitter.on('roof:leave', onRoofLeave)
     emitter.on('tool:cancel', onCancel)
 
     return () => {
@@ -363,6 +495,10 @@ const WindowTool: React.FC = () => {
       emitter.off('wall:move', onWallMove)
       emitter.off('wall:click', onWallClick)
       emitter.off('wall:leave', onWallLeave)
+      emitter.off('roof:enter', onRoofHover)
+      emitter.off('roof:move', onRoofHover)
+      emitter.off('roof:click', onRoofClick)
+      emitter.off('roof:leave', onRoofLeave)
       emitter.off('tool:cancel', onCancel)
     }
   }, [])

packages/viewer/src/lib/materials.ts

@@ -71,7 +71,7 @@ export function resolveSurfaceColor(
   // The active scene theme may tint individual roles (e.g. Mediterranean's blue
   // roof); fall back to the chosen colour preset's palette when it doesn't.
   const tints = sceneThemeId ? getSceneTheme(sceneThemeId).clayTints : undefined
-  return tints?.[role] ?? PRESET_PALETTES[preset][role]
+  return tints?.[role] ?? (PRESET_PALETTES[preset] ?? CLAY_PALETTE)[role]
 }
 
 // DoubleSide on any NodeMaterial inside the MRT scenePass (SSGI's output /

packages/viewer/src/store/use-viewer.ts

@@ -7,6 +7,7 @@ import { create } from 'zustand'
 import { persist } from 'zustand/middleware'
 import type { EdgeMode } from '../lib/edge-style'
 import type { ColorPreset, RenderShading } from '../lib/materials'
+import { SCENE_THEME_IDS } from '../lib/scene-themes'
 
 export type RenderContext = 'editor' | 'viewer'
 
@@ -114,6 +115,85 @@ type ViewerState = {
   setInputDragging: (dragging: boolean) => void
 }
 
+type PersistedViewerState = Partial<
+  Pick<
+    ViewerState,
+    | 'cameraMode'
+    | 'sceneTheme'
+    | 'shadingByContext'
+    | 'textures'
+    | 'colorPreset'
+    | 'edges'
+    | 'shadows'
+    | 'unit'
+    | 'levelMode'
+    | 'wallMode'
+    | 'projectPreferences'
+  >
+>
+
+const CAMERA_MODES = ['perspective', 'orthographic'] as const
+const RENDER_SHADINGS = ['solid', 'rendered'] as const
+const COLOR_PRESETS = ['clay', 'white', 'mono', 'blueprint'] as const
+const EDGE_MODES = ['off', 'soft', 'strong'] as const
+const UNITS = ['metric', 'imperial'] as const
+const LEVEL_MODES = ['stacked', 'exploded', 'solo', 'manual'] as const
+const WALL_MODES = ['up', 'cutaway', 'down'] as const
+
+function pickString<T extends string>(value: unknown, allowed: readonly T[], fallback: T): T {
+  return typeof value === 'string' && allowed.includes(value as T) ? (value as T) : fallback
+}
+
+function normalizeShadingByContext(value: unknown): ViewerState['shadingByContext'] {
+  if (!value || typeof value !== 'object' || Array.isArray(value)) return {}
+
+  const next: ViewerState['shadingByContext'] = {}
+  for (const [context, shading] of Object.entries(value)) {
+    if (context !== 'editor' && context !== 'viewer') continue
+    next[context] = pickString<RenderShading>(shading, RENDER_SHADINGS, 'rendered')
+  }
+  return next
+}
+
+function normalizeProjectPreferences(value: unknown): ViewerState['projectPreferences'] {
+  if (!value || typeof value !== 'object' || Array.isArray(value)) return {}
+
+  const next: ViewerState['projectPreferences'] = {}
+  for (const [projectId, preferences] of Object.entries(value)) {
+    if (!preferences || typeof preferences !== 'object' || Array.isArray(preferences)) continue
+    const record = preferences as Record<string, unknown>
+    next[projectId] = {
+      ...(typeof record.showScans === 'boolean' ? { showScans: record.showScans } : {}),
+      ...(typeof record.showGuides === 'boolean' ? { showGuides: record.showGuides } : {}),
+      ...(typeof record.showGrid === 'boolean' ? { showGrid: record.showGrid } : {}),
+    }
+  }
+  return next
+}
+
+function normalizePersistedViewerState(value: unknown): PersistedViewerState {
+  if (!value || typeof value !== 'object' || Array.isArray(value)) return {}
+  const state = value as Record<string, unknown>
+
+  return {
+    cameraMode: pickString<ViewerState['cameraMode']>(
+      state.cameraMode,
+      CAMERA_MODES,
+      'perspective',
+    ),
+    sceneTheme: pickString(state.sceneTheme, SCENE_THEME_IDS, 'studio'),
+    shadingByContext: normalizeShadingByContext(state.shadingByContext),
+    textures: typeof state.textures === 'boolean' ? state.textures : true,
+    colorPreset: pickString<ColorPreset>(state.colorPreset, COLOR_PRESETS, 'clay'),
+    edges: pickString<EdgeMode>(state.edges, EDGE_MODES, 'soft'),
+    shadows: typeof state.shadows === 'boolean' ? state.shadows : true,
+    unit: pickString<ViewerState['unit']>(state.unit, UNITS, 'metric'),
+    levelMode: pickString<ViewerState['levelMode']>(state.levelMode, LEVEL_MODES, 'stacked'),
+    wallMode: pickString<ViewerState['wallMode']>(state.wallMode, WALL_MODES, 'up'),
+    projectPreferences: normalizeProjectPreferences(state.projectPreferences),
+  }
+}
+
 const useViewer = create<ViewerState>()(
   persist(
     (set) => ({
@@ -267,6 +347,10 @@ const useViewer = create<ViewerState>()(
     }),
     {
       name: 'viewer-preferences',
+      merge: (persistedState, currentState) => ({
+        ...currentState,
+        ...normalizePersistedViewerState(persistedState),
+      }),
       partialize: (state) => ({
         cameraMode: state.cameraMode,
         sceneTheme: state.sceneTheme,

packages/viewer/src/systems/ceiling/ceiling-system.tsx

@@ -133,6 +133,8 @@ export function generateCeilingGeometry(
     // the whole command encoder.
     const degenerate = new THREE.BufferGeometry()
     degenerate.setAttribute('position', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
+    degenerate.setAttribute('normal', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
+    degenerate.setAttribute('uv', new THREE.Float32BufferAttribute(new Float32Array(6), 2))
     return degenerate
   }
 

packages/viewer/src/systems/item/item-system.tsx

@@ -36,12 +36,20 @@ export const ItemSystem = () => {
       if (!mesh) return
 
       if (item.asset.attachTo === 'wall-side') {
-        // Wall-attached item: offset Z by half the parent wall's thickness
-        const parentWall = item.parentId ? nodes[item.parentId as AnyNodeId] : undefined
-        if (parentWall && parentWall.type === 'wall') {
-          const wallThickness = (parentWall as WallNode).thickness ?? 0.1
+        // Wall-attached item: offset Z by half the host wall's thickness.
+        // Roof-segment wall faces share the convention — the face frame's
+        // z = 0 is the wall mid-plane, so the same push lands the item on
+        // the outer surface.
+        const parent = item.parentId ? nodes[item.parentId as AnyNodeId] : undefined
+        const thickness =
+          parent?.type === 'wall'
+            ? ((parent as WallNode).thickness ?? 0.1)
+            : parent?.type === 'roof-segment'
+              ? (parent.wallThickness ?? 0.1)
+              : undefined
+        if (thickness !== undefined) {
           const side = item.side === 'front' ? 1 : -1
-          mesh.position.z = (wallThickness / 2) * side
+          mesh.position.z = (thickness / 2) * side
         }
       }
 

packages/viewer/src/systems/roof/roof-system.tsx

@@ -110,7 +110,13 @@ export const RoofSystem = () => {
       // previous cut shape (stale CSG) once the user exits segment
       // edit mode. Registry-driven so the viewer stays kind-agnostic.
       const def = nodeRegistry.get(node.type)
-      if (def?.capabilities?.roofAccessory) {
+      // Kinds with `dirtyHandledByOwnSystem` (door / window) reach the roof
+      // through their own geometry system's parentId cascade instead —
+      // their dirty marks belong to that system, not to this loop.
+      if (
+        def?.capabilities?.roofAccessory &&
+        !def.capabilities.roofAccessory.dirtyHandledByOwnSystem
+      ) {
         const segId = (node as { roofSegmentId?: string }).roofSegmentId
         const seg = segId ? (nodes[segId as AnyNodeId] as RoofSegmentNode | undefined) : undefined
         if (seg?.parentId) {
@@ -131,10 +137,20 @@ export const RoofSystem = () => {
           // Only compute expensive individual CSG when the segment is actually rendered
           // (its parent group is visible = the roof is selected for editing)
           const isVisible = mesh.parent?.visible !== false
-          if (isVisible && segmentsProcessed < MAX_SEGMENTS_PER_FRAME) {
-            updateRoofSegmentGeometry(effectiveSegment, mesh)
+          // Accessory-reveal mode (RoofEditSystem): the wrapper is shown so
+          // portaled handles render, but the merged shell stays visible and
+          // the segment meshes are stripped to empty placeholders. Rebuilding
+          // per-segment CSG here would draw UNCUT geometry on top of the
+          // merged shell — hiding a freshly cut opening (door / window /
+          // skylight) until the next deselect. Full edit mode hides the
+          // merged mesh, so gate the rebuild on its visibility.
+          const revealOnly =
+            mesh.parent?.name === 'segments-wrapper' &&
+            mesh.parent?.parent?.getObjectByName('merged-roof')?.visible === true
+          if (isVisible && !revealOnly && segmentsProcessed < MAX_SEGMENTS_PER_FRAME) {
+            updateRoofSegmentGeometry(effectiveSegment, mesh, nodes)
             segmentsProcessed++
-          } else if (isVisible) {
+          } else if (isVisible && !revealOnly) {
             return // Over budget — keep dirty, process next frame
           } else {
             // Just sync transform, skip CSG — the merged roof handles visuals.
@@ -152,6 +168,14 @@ export const RoofSystem = () => {
                 'position',
                 new THREE.Float32BufferAttribute(new Float32Array(9), 3),
               )
+              placeholder.setAttribute(
+                'normal',
+                new THREE.Float32BufferAttribute(new Float32Array(9), 3),
+              )
+              placeholder.setAttribute(
+                'uv',
+                new THREE.Float32BufferAttribute(new Float32Array(6), 2),
+              )
               computeGeometryBoundsTree(placeholder)
               mesh.geometry = placeholder
             }
@@ -210,8 +234,12 @@ export const RoofSystem = () => {
 // GEOMETRY GENERATION
 // ============================================================================
 
-function updateRoofSegmentGeometry(node: RoofSegmentNode, mesh: THREE.Mesh) {
-  const newGeo = generateRoofSegmentGeometry(node)
+function updateRoofSegmentGeometry(
+  node: RoofSegmentNode,
+  mesh: THREE.Mesh,
+  nodes?: Record<string, AnyNode>,
+) {
+  const newGeo = generateRoofSegmentGeometry(node, nodes)
 
   mesh.geometry.dispose()
   mesh.geometry = newGeo
@@ -221,6 +249,89 @@ function updateRoofSegmentGeometry(node: RoofSegmentNode, mesh: THREE.Mesh) {
   mesh.rotation.y = node.rotation
 }
 
+/**
+ * Subtract every hosted accessory cut (`capabilities.roofAccessory.
+ * buildCut`) from a segment's brushes, in SEGMENT-LOCAL space. Shared by
+ * the merged-shell path AND the per-segment path (full edit mode /
+ * painted segments) — without the latter, selecting a segment used to
+ * swap the merged shell for uncut per-segment meshes and every door /
+ * window / skylight hole vanished until deselect. Children are read
+ * live-effective so an in-flight handle drag carves the live hole.
+ * Registry-driven so the viewer never names a kind.
+ */
+function subtractAccessoryCuts(
+  brushes: { deckSlab: Brush; shinSlab: Brush; wallBrush: Brush; innerBrush: Brush },
+  segment: RoofSegmentNode,
+  nodes: Record<string, AnyNode>,
+) {
+  let workingShin = brushes.shinSlab
+  let workingDeck = brushes.deckSlab
+  let workingWall = brushes.wallBrush
+  for (const childElemId of segment.children ?? []) {
+    const storedChild = nodes[childElemId as AnyNodeId]
+    if (!storedChild) continue
+    const childElem = getEffectiveNode(storedChild)
+    const meta =
+      typeof childElem.metadata === 'object' && childElem.metadata !== null
+        ? (childElem.metadata as Record<string, unknown>)
+        : undefined
+    if (meta?.isTransient) continue
+
+    const childDef = nodeRegistry.get(childElem.type)
+    const buildCut = childDef?.capabilities?.roofAccessory?.buildCut
+    if (!buildCut) continue
+
+    const cutGeo = buildCut(childElem, segment)
+    if (!cutGeo) continue
+
+    // Wrap the kind-emitted geometry in a Brush. Kinds return raw
+    // shapes; the viewer welds (mandatory after rotations leave
+    // duplicated verts), attaches a single material group, and
+    // builds the bounds tree — keeping kind code free of
+    // three-bvh-csg / three-mesh-bvh imports.
+    const welded = mergeVertices(cutGeo, 1e-4)
+    cutGeo.dispose()
+    const idxCount = welded.getIndex()?.count ?? 0
+    if (idxCount === 0) {
+      welded.dispose()
+      continue
+    }
+    welded.clearGroups()
+    welded.addGroup(0, idxCount, 0)
+    welded.computeVertexNormals()
+    computeGeometryBoundsTree(welded)
+    const cut = new Brush(welded, dummyMats[0])
+    cut.updateMatrixWorld()
+
+    const cutScope = childDef?.capabilities?.roofAccessory?.cutScope ?? 'all'
+    try {
+      if (cutScope !== 'wall') {
+        const nextShin = csgEvaluator.evaluate(workingShin, cut, SUBTRACTION) as Brush
+        workingShin.geometry.dispose()
+        prepareBrushForCSG(nextShin)
+        workingShin = nextShin
+
+        const nextDeck = csgEvaluator.evaluate(workingDeck, cut, SUBTRACTION) as Brush
+        workingDeck.geometry.dispose()
+        prepareBrushForCSG(nextDeck)
+        workingDeck = nextDeck
+      }
+
+      const nextWall = csgEvaluator.evaluate(workingWall, cut, SUBTRACTION) as Brush
+      workingWall.geometry.dispose()
+      prepareBrushForCSG(nextWall)
+      workingWall = nextWall
+    } catch (e) {
+      console.error(`[${childElem.type}] cut CSG failed:`, e)
+    } finally {
+      cut.geometry.dispose()
+    }
+  }
+  brushes.shinSlab = workingShin
+  brushes.deckSlab = workingDeck
+  brushes.wallBrush = workingWall
+}
+
 function updateMergedRoofGeometry(
   roofNode: RoofNode,
   group: THREE.Group,
@@ -261,74 +372,7 @@ function updateMergedRoofGeometry(
     const brushes = getRoofSegmentBrushes(child)
     if (!brushes) continue
 
-    // Per-child cuts in SEGMENT-LOCAL space: subtract every accessory
-    // that contributes a cut (declares
-    // `capabilities.roofAccessory.buildCut`) from shin / deck / wall
-    // before we accumulate. Mirrors roof-system v1 — the cut is built
-    // in segment-local, then carved out before the segment transform
-    // stacks on. Registry-driven so the viewer never names a kind.
-    let workingShin = brushes.shinSlab
-    let workingDeck = brushes.deckSlab
-    let workingWall = brushes.wallBrush
-    for (const childElemId of child.children ?? []) {
-      const childElem = nodes[childElemId as AnyNodeId]
-      if (!childElem) continue
-      const meta =
-        typeof childElem.metadata === 'object' && childElem.metadata !== null
-          ? (childElem.metadata as Record<string, unknown>)
-          : undefined
-      if (meta?.isTransient) continue
-
-      const childDef = nodeRegistry.get(childElem.type)
-      const buildCut = childDef?.capabilities?.roofAccessory?.buildCut
-      if (!buildCut) continue
-
-      const cutGeo = buildCut(childElem, child)
-      if (!cutGeo) continue
-
-      // Wrap the kind-emitted geometry in a Brush. Kinds return raw
-      // shapes; the viewer welds (mandatory after rotations leave
-      // duplicated verts), attaches a single material group, and
-      // builds the bounds tree — keeping kind code free of
-      // three-bvh-csg / three-mesh-bvh imports.
-      const welded = mergeVertices(cutGeo, 1e-4)
-      cutGeo.dispose()
-      const idxCount = welded.getIndex()?.count ?? 0
-      if (idxCount === 0) {
-        welded.dispose()
-        continue
-      }
-      welded.clearGroups()
-      welded.addGroup(0, idxCount, 0)
-      welded.computeVertexNormals()
-      computeGeometryBoundsTree(welded)
-      const cut = new Brush(welded, dummyMats[0])
-      cut.updateMatrixWorld()
-
-      try {
-        const nextShin = csgEvaluator.evaluate(workingShin, cut, SUBTRACTION) as Brush
-        workingShin.geometry.dispose()
-        prepareBrushForCSG(nextShin)
-        workingShin = nextShin
-
-        const nextDeck = csgEvaluator.evaluate(workingDeck, cut, SUBTRACTION) as Brush
-        workingDeck.geometry.dispose()
-        prepareBrushForCSG(nextDeck)
-        workingDeck = nextDeck
-
-        const nextWall = csgEvaluator.evaluate(workingWall, cut, SUBTRACTION) as Brush
-        workingWall.geometry.dispose()
-        prepareBrushForCSG(nextWall)
-        workingWall = nextWall
-      } catch (e) {
-        console.error(`[${childElem.type}] cut CSG failed:`, e)
-      } finally {
-        cut.geometry.dispose()
-      }
-    }
-    brushes.shinSlab = workingShin
-    brushes.deckSlab = workingDeck
-    brushes.wallBrush = workingWall
+    subtractAccessoryCuts(brushes, child, nodes)
 
     _matrix.compose(
       _position.set(child.position[0], child.position[1], child.position[2]),
@@ -789,13 +833,20 @@ export function getRoofSegmentBrushes(
   return null
 }
 
-export function generateRoofSegmentGeometry(node: RoofSegmentNode): THREE.BufferGeometry {
+export function generateRoofSegmentGeometry(
+  node: RoofSegmentNode,
+  nodes?: Record<string, AnyNode>,
+): THREE.BufferGeometry {
   const brushes = getRoofSegmentBrushes(node)
   if (!brushes) {
     // Fallback: simple box
     return new THREE.BoxGeometry(node.width, node.wallHeight, node.depth)
   }
 
+  if (nodes) {
+    subtractAccessoryCuts(brushes, node, nodes)
+  }
+
   const { deckSlab, shinSlab, wallBrush, innerBrush } = brushes
   let resultGeo = new THREE.BufferGeometry()
 

packages/viewer/src/systems/stair/stair-system.tsx

@@ -531,6 +531,8 @@ function createEmptyGeometry(): THREE.BufferGeometry {
   // unbound and the draw is rejected ("Vertex buffer slot 0 … was not set"),
   // poisoning the command encoder. The count-0 groups keep nothing drawn.
   geometry.setAttribute('position', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
+  geometry.setAttribute('normal', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
+  geometry.setAttribute('uv', new THREE.Float32BufferAttribute(new Float32Array(6), 2))
   geometry.addGroup(0, 0, STAIR_TREAD_MATERIAL_INDEX)
   geometry.addGroup(0, 0, STAIR_SIDE_MATERIAL_INDEX)
   return geometry